Actor Gary Sinise shared the pain of watching his son bravely battle cancer but also emphasized how the power of prayer and deep faith rendered hope and support during the heartbreaking tribulations that took the life of a "man of great faith."

In August 2018, McCanna Anthony "Mac" Sinise was diagnosed with chordoma — a very rare, slow-growing cancer that forms in the spine or base of the skull. Mac underwent surgery to remove the first tumor in September 2018. Sadly, the cancer returned by May 2019.

Sinise recently told Christian Broadcasting Network, "It had come back, and it was starting to spread throughout his body. He was back in the hospital again, and he started chemo and radiation at that point, but there is no cure for this particular cancer. There’s no reliable drug that has been used to fight it that has been effective."

Sinise characterized the clash with cancer as "very disabling and crippling." He noted that the tumors were "growing very fast," which is uncharacteristic for chordoma.

Mac endured several unforgiving treatments, debilitating medications, excruciating surgeries, and extended hospital visits.

Making matters even worse, Gary's wife, Moira, was diagnosed with stage 3 breast cancer in the summer of 2018. She too was undergoing surgeries, chemotherapy, and radiation. After several months of treatment, Moira's cancer went into remission.

Mac was not as fortunate — the cancer was spreading throughout his body.

By November 2018, Mac had gone through his third spinal surgery to remove the tumors. At that point, Mac was so disabled by the cancer that he could no longer come into the office where he worked as an assistant manager at the Gary Sinise Foundation. The cancer eventually forced him to resign from his position in his father's charity.

Sinise confessed, "Have there been times where I just kind of fell down on the stairs and kind of let the emotion out … because, at times, I didn’t know what else to do? I was trying to do everything I could to find solutions for Mac and his cancer."

During his grueling fight against cancer, Mac "loved his Catholic faith" and embraced his religion to give him strength.

Sinise told CBN, "It was just inspiring to see how it helped sustain him through this cancer battle."

To help him through his courageous journey, Mac also drew solace from the power of prayer, wrote journals, and revisited his passion for creating music.

Mac had been a drummer since the age of nine and would even be a substitute drummer in Sinise's Lt. Dan Band — a musical group that catered to wounded veterans at military hospitals across the country.

However, the cancer robbed Mac's ability to play the drums and piano since the cancer had mostly paralyzed him from the neck down.

Sinise recalled, "Early 2023, he said to me, 'Dad, you know, there’s some music that I never finished in college, and I think I’d like to try to finish it.' And he hadn’t been thinking about music much at all, really, but early 2023, he starts talking about that."

From his hospital bed, Mac finished a song that he had started in his college days.

Mac was a graduate of the USC Thornton School of Music. He reconnected with Oliver Schnee – an old friend from college and a composer. Schnee orchestrated and produced Mac's piece of music titled "Arctic Circles."

On July 17, 2023, the "Arctic Circles" song was recorded at the prominent Sunset Sound recording studio in Los Angeles, California.

Sinise recalled, "I was just a sobbing mess when I went to the recording studio with him because he hadn’t played any of it for me at all. I had never heard it when he wrote it in college."

The proud father added, "I was so unprepared for what I was going to hear. It was all a surprise, and it was all a beautiful, beautiful moment to hear."

Mac Sinise - Arctic Circles www.youtube.com

Moira encouraged Mac to satisfy his musical thirst by playing the harmonica, which he taught himself to play.

Mac recorded two more music sessions in Tennessee with his original pieces, where he played harmonica with members of the Lt. Dan Band, including his father on the bass.

The musical troupe performed a cover of the old American folk song "Red River Valley," which his mother used to sing to him and his sisters when they were small children.

The sessions were recorded at the renowned Blackbird Studios in Nashville, where songs have been recorded by music stars such as Taylor Swift, Keith Urban, and Tim McGraw.

Mac celebrated his 33rd birthday by recording songs with a full orchestra at the studio and featured a special appearance by accomplished singer Harry Connick Jr.

Mac Sinise - A Surprise Visit From Harry Connick, Jr. At The Studio www.youtube.com

The "Forrest Gump" star revealed that Mac had "fulfilled his dream" by recording his original music.

"He accomplished what he was looking to do, and he was happy at the end of his life — and that’s comforting for our family for sure," Sinise said.

Despite all of the struggles and overwhelming tribulations, Mac turned to music and faith to help him persevere.

"I know his faith played a strong part in helping to sustain him through this battle," Sinise explained. "And I was there with him every step of the way in these hospital stays and with [him] those final days before he died and saw him struggling. But I knew that he was fulfilled with what he’d accomplished at the end."

Sinise described his brave son as "a man of great faith — great, great faith."

However, Mac was fighting an extremely difficult uphill battle. The young man embraced his faith and turned to consistently reading a St. Augustine prayer book – where he underlined text and wrote his thoughts pertaining to his fight for his life.

"That was his special prayer book that he left his mother," Sinise stated. "He wrote in it, 'At my passing, give to mom,' and a lot of things [are] underlined in there."

Sinise admitted the crushing pain of watching the life escape from his son.

"In all my 69 years … sorrowful moments or painful moments along the way, I’ve never experienced a sorrow and a pain like this," Sinise lamented. "He was beginning to let go. The fight was going out of him."

McCanna Anthony "Mac" Sinise passed away at 3:25 p.m. on Jan. 5, 2024, at the young age of 33 following a lengthy and tragic cancer battle.

Sinise was serenaded with an outpouring of heartfelt condolences over his son's tragic passing.

Mac left loved ones a portal into his soul that documented his most trying times.

"I’ve discovered a lot of stuff on his iPhone and iPad that he wrote, even things that he recorded, you know, selfies of him talking to the camera about what he was thinking and what he was feeling," Sinise revealed. "And, so I knew he was preparing himself as much as possible, and my job was just to keep trying to find drugs, keep trying to fight, and I never wanted to give up, even in the hospital in those final days."

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