Heartbroken Gary Sinise has opened up about his son’s final hours before a rare cancer took his life at just 33 in 2024.The 71-year-old actor, best known for portraying Lieutenant Dan in 1994’s Forrest Gump, said he struggled to comprehend his beloved son McCanna ‘Mac’ Sinise was facing the end of his life following a five-year battle with spinal cancer Chordoma.Mac was diagnosed in August 2018 with the debilitating disease, which left him confined to a wheelchair as the nerve damage from multiple ‘rock-sized’ tumors and surgeries had paralyzed him from the chest down – and breathing with a cannula. Chordoma is part of a family of cancers called sarcoma, which include cancers of the bones, cartilage, muscles and other connective tissue and is generally slow growing, but are relentless and tend to recur after treatment according to the Chordoma Foundation. It only affects 300 people in the US per year. In a new memoir, Graceful Warrior, released on November 10, Sinise details the hours leading up to Mac’s death on January 5, 2024 – revealing he knew he was losing his son when he lost the ability to breathe, even with assistance after being admitted to the hospital on December 30, 2023.Sinise writes: ‘I was so proud of Mac. I loved him so much. He had fought so hard, and I had fought with him, never letting thoughts of defeat creep in. Yet I could see that, despite all our efforts over the past few days, he would not return to the place where he could simply use a cannula to breathe.’ Heartbroken Gary Sinise has opened up about his son’s final hours before a rare cancer took his life at just 33 The 71-year-old actor, best known for portraying Lieutenant Dan in 1994’s Forrest Gump, said he struggled to comprehend his beloved son McCanna ‘Mac’ Sinise was facing the end of his life following a five year battle with spinal cancer Chordoma (Above in 2023) Sinise called family members to the hospital at 7am, with Mac’s mother Moira, 72, and sisters Sophie, 37, and Ella, 34, gathering at his bedside.’Already I felt completely worn out, but I knew I needed to walk my family through this difficult and sacred day. After everyone arrived, I took them into the private room and tried to tell them as best I could what the night and early morning had been like. It was tough for me, seeing all their faces’, he said, per an excerpt obtained by EW.After a priest delivered Mac the last rites, Sinise writes, ‘We surrounded Mac with love. Holding hands. Tears in our eyes. A Rosary was said for a bit. His mask was off now. We could see his face. Everyone with us. Family. By now, the doctors said Mac could no longer hear us, but I am sure he knew we were there. He was peaceful.’Mac died at 3.25pm – with Sinise saying losing his only son ‘didn’t seem real’ and that he could ‘still feel Mac’s winsomeness, his resilience, his grace, his courage, his faith, and the strength that had carried him through.’Sinise stayed by Mac’s bedside after he died ‘studying him, remembering him.’ The CSI: NY actor previously recounted the immense physical toll Mac’s cancer took on him in a feature published by People magazine last week.’His chest looked like rocks were pressing out from beneath his skin,’ Sinise said. ‘He was such a light,’ older daughter Sophie said. ‘He made you feel better when you walked in the room.’Mac’s was not the only devastating diagnosis in the family as two months prior, Sinise’s wife Moira had been diagnosed with stage 3 breast cancer. In new memoir, Graceful Warrior, released on November 10, Sinise details the hours leading up to Mac’s death on January 5, 2024 – revealing he knew he was losing his son when he lost the ability to breathe, even with assistance After a priest delivered Mac the last rites, Sinise writes, ‘We surrounded Mac with love. Holding hands. Tears in our eyes. A Rosary was said for a bit. His mask was off now. We could see his face’ Mac died at 3.25pm – with Sinise saying losing his only son ‘didn’t seem real’ and that he could ‘still feel Mac’s winsomeness’ With both his daughters unable to care for Mac and Moira due to family and career obligations, Sinise took it upon himself to take the lead in caretaking duties while also juggling a gig on popular Netflix series 13 Reasons Why and attending events for his Gary Sinise Foundation, which gives aid to veterans and first responders.And when that aforementioned series ended in 2020, the Of Mice and Men star took it upon himself to step away from acting entirely.Sinise said: ‘Family was the priority. One of the blessings is that I had succeeded in Hollywood, and I could afford to be there for my family 24/7.’As if that wasn’t already enough, the actor even tried to research Chordoma as much as he could in order to try and save his beloved son.The actor explained: ‘Mac tried 25 different drugs over a four-and-a-half year period. I never lost hope that we were going to hit the sweet spot.’Unfortunately, Mac’s condition took a turn for the worse as he lost his ability to move but still kept pushing as he continued to practice his Catholic faith at mass, learned to play harmonica, and even watched Chicago Cubs games and prayed alongside his mom while both in wheelchairs.Sinise likened Mac’s fighting spirit to the hero soldier in Sam Mendes’s Oscar winning war epic 1917 who was ‘running through the battlefield, bombs knocking you down, and you’re still getting back up.”We didn’t get the miracle we were all praying for, but there were other miracles, like the way Mac lived his life. He sure showed us grace under fire.’Sinise revealed that his son had passed away following a years-long battle with the rare spinal cancer Chordoma in a post shared to the Gary Sinise Foundation’s website at the time.Mac had worked with the foundation and had supported his father’s Lt Dan Band as a fill-in drummer until repeated spinal surgeries and the advancement of his cancer in recent years forced him to step away.’I am so blessed, fortunate, and proud to be his dad,’ Sinise wrote in his moving obituary. Sinise has had numerous acclaimed film and television roles in a decades-long career, but he is best known for playing Lt. Dan in the Tom Hanks–starring blockbuster Forrest Gump (pictured) In February 2024, Gary revealed that his son had passed away following a years-long battle with the rare spinal cancer Chordoma in a post shared to the Gary Sinise Foundation’s website In a lengthy tribute to his son, Sinise recalled the twin tragedies of 2018, when his wife Moira was diagnosed with stage three breast cancer in June, before Mac received his chordoma diagnosis in August. Despite his worsening condition and difficult treatments, Sinise wrote that his son continued to come into the foundation’s office regularly, and after he was unable to he continued to work behind the scenes.The actor revealed that Mac’s final project for the foundation was a podcast interview with father and son. Even after he stepped back to focus on his treatments and health, Mac turned to one of his passions: music.Sinise wrote that his son could no longer play his main instruments, drums and piano, so he assumed ‘music was a thing of the past.’Mac had studied at the University of Southern California’s Thornton School of Music, where he had begun work on an unfinished composition later titled Arctic Circles – ‘inspired by the wintery nature shows he loved watching while lying in his hospital bed’ – and he became determined to complete it before his time was up.’The cancer had paralyzed him from the chest down, but he still had limited use of his right arm, and fingers on his left hand,’ Sinise explained.Mac could still select musical notes with a stylus strapped to his hand, and members of his dad’s Lt Dan Band collaborated with him to hone the piece.Mac’s friend from USC, the composer Oliver Schnee, also collaborated with him to make the final touches on the arrangement, before Mac paid for recording sessions. The two worked together to record more of Mac’s originals, as well as traditional songs, to flesh out an album titled Resurrection & Revival Mac celebrated his 33rd birthday during his November 10 recording session on his expanded album, with Gary playing bass on one tune at his son’s requestBut Sinise revealed that Mac was struggling to breathe and was forced to go to the hospital on December 30, 2023, where he would remain to the end.Mac lived long enough to complete his album, but he died on January 5, the same week that the album went to press, and Sinise revealed that his son was laid to rest on January 23.’Like any family experiencing such a loss, we are heartbroken and have been managing as best we can,’ Sinise wrote. ‘As parents, it is so difficult losing a child.’The actor, who has performed with his band at numerous events honoring members of the armed services over the years, extended his thoughts to others who had lost loved ones too.Sinise, who noted that Mac battled cancer for five-and-a-half years, wrote: ‘While our hearts ache at missing him, we are comforted in knowing that Mac is no longer struggling, and inspired and moved by how he managed it. ‘Thank you, Mac. You did it. Resurrection & Revival will live on. And so will you. In our hearts forever,’ Sinise concluded his tribute. ‘We will miss you and love you for eternity”We were blessed to have you in our lives as son, brother, and friend…and we will miss you and love you for eternity,’ he wrote, before signing off as the ‘Proud father of Mac Sinise.’ ‘He fought an uphill battle against a cancer that has no cure, but he never quit trying,’ he added.Sinise emphasized that his family’s story was ‘not unique,’ but he took inspiration from the many soldiers he had met over the years who had persevered with their own struggles. ‘I have learned from them and been inspired by them,’ he wrote, adding, ‘Knowing them gave me strength.’The screen star continued: ‘Our family is grateful for all those who have helped us, loved us, and supported us in this fight.’ He concluded by addressing his late son directly.’Thank you, Mac. You did it. Resurrection & Revival will live on. And so will you. In our hearts forever.’Graceful Warrior: The True Story of a Son, a Father, and a Family Who Carried Each Other Through is out now.