Actor Gary Sinise is opening up about the “beautiful” impact music had on his late son’s life.

Late last month, Sinise — the 68-year-old film star known for his role in Forrest Gump — announced that his 33-year-old son Mac had died of an extremely rare form of spinal cancer. Mac, who was born MacCanna Anthony Sinise, was diagnosed in 2018 and underwent surgery to remove his tumor, but unfortunately, the cancer recurred.

However, during the last year of his life, Sinise says that Mac found his way back to a passion for music that he first fostered as a young boy.

“I bought him his first drum set when he was nine years old. He started playing,” the actor explains to Entertainment Tonight, going on to say that his son played throughout school, even attending a special music program for college. Not only was Mac playing music, but he began writing music, too.

“And he created a bunch of pieces of music while he was at college that kinda got, he just put ’em away and didn’t do anything with them,” Sinise continues. “About January of 2023, he said, ‘Dad, I think I wanna try to finish this music that I worked on all those years ago in college.”

Sinise has a musical side of his own: Though he’s best known for his acting work, he has also performed as part of the Lt. Dan Band since 2004. The rock cover group shares its name with Lieutenant Dan Taylor, Sinise’s Forrest Gump character, and frequently plays morale-boosting sets for military bases and service members and their families.

Mac grew up around his dad’s bandmates, so Sinise connected him with some of them to work on completing his music. Listening to the finished product was emotional, the actor admits.

“The music is powerful. It’s beautiful. It’s uplifting. It’s inspirational,” he says. “And then to tack on the story on top of that, of a guy who was completely broken physically, yet spiritually and creatively and faithfully, he was living his life. That’s a beautiful thing.”

Now, Sinise says his son’s story is an inspiration to him — and hopefully, to others too.

“If telling his story can inspire others to just persevere through their own challenges and keep at it and never quit, never give up, never give up living — then that’s a good thing. That’s a reason to share it,” he affirms.

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Mac Sinise died on Jan. 5. As the family continues to grieve, his actor father reflected on the healing that his music continues to bring.

“Somehow it feels like he’s just on vacation, like he’s gonna come back. I can’t say we’re enjoying what’s going on, but we are filled with joy that so many people are discovering his music talent,” Sinise points out. “Because he put that away. He thought that was a thing of the past.”