The MacSinise family is mourning a tragic loss. 

Gary Sinise's son McCanna "Mac" Sinise died at age 33 on Jan. 5, more than five years after being diagnosed with a rare form of bone cancer called Chordoma, the Forrest Gump actor shared on Feb. 27. 

"Like any family experiencing such a loss, we are heartbroken and have been managing as best we can," he wrote in a Feb. 27 statement on the Gary Sinise Foundation website. "As parents, it is so difficult losing a child. My heart goes out to all who have suffered a similar loss, and to anyone who has lost a loved one."

And while Gary and his wife Moira Harris—who also share daughters Ella Sinise, 32, and Sophie Sinise, 35—called his death "heartbreaking," the couple also expressed feeling thankful their son will no longer have to suffer. 

"Our family's cancer fight lasted for 5 ½ years, and it became more and more challenging as time went on," his statement continued. "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."

The letter added, "He fought an uphill battle against a cancer that has no cure, but he never quit trying. Mac loved movies, and we always told him he reminded us of the soldier at the end of the extraordinary film 1917, running through the battlefield, bombs going off all around him, knocking him down one after the other, yet he keeps getting back up, refusing to quit and keeps running forward."

Mac was diagnosed with his rare form of cancer in 2018—two months after Moira learned she had breast cancer, according to the CSI: NY star. While Moira went into remission and is cancer-free, Mac's treatment sadly wasn't as effective. 

"With Mac, after surgery to remove the initial tumor in September of 2018, and another spine procedure in February 2019 to clear what looked like an infection," Gary said, "unfortunately a follow up scan in May of 2019 would show that his Chordoma had come back and was spreading."

In addition to his statement, the 68-year-old shared a series of photos of his son doing the things he loved, including playing the drums, producing his own album titled Mac Sinise: Resurrection and Revival and working in education outreach at the Gary Senise Foundation, which aims to create programs that honor "our defenders, veterans, first responders, their families and those in need."

"Mac was truly a light for all of us," Gary said in closing. "An incredible inspiration to those who knew and loved him, he faced his battle with grace, courage, and love. Even with one setback after another, he never stopped living and learning, creating, and giving and loving."