Gary Sinise’s Heartbreaking Farewell to His Son In January, Gary Sinise tragically lost his 33-year-old son, McCanna “Mac” Sinise, to cancer. Despite the heartbreak, Gary has shared tearful details of Mac’s final days, revealing his son’s incredible courage and peace. Mac, a talented musician, completed a music album during his last week of life. He found joy in his accomplishments, even as his illness progressed. Gary recalls a bittersweet moment when Mac watched Forrest Gump in his hospital bed, finding comfort in his father’s work. Mac battled a rare cancer for years, undergoing 25 different treatments and fighting until the end. Paralyzed by the disease, he still radiated resilience and positivity. “He was happy at the end of his life,” Gary said