Gary Sinise isn't sure if he'll return to acting after his son's death

He told PEOPLE magazine: "That's when I stopped acting. I started putting everything I had into trying to find a miracle for Mac."

Mac - who was diagnosed with a rare form of spinal cancer in 2018 - died aged 33 last year.

His father - whose most recent roles were in '13 Reasons Why', I still Believe' and 'Joe Bell' - is concentrating on his family rather than thinking about an acting comeback.

He said: "Something may come along and it'll be right, but it's harder to leave home now. I just want to be around family.

"Since losing Mac, I hold my daughters a lot tighter. You think about the things that are really important."

Gary has five grandchildren from his daughters Sophia, 36, and Ella, 32, and his eldest admitted he "spoils them rotten".

During Mac's final months, Gary admitted he was essentially his son's "air traffic controller". He explained: "I didn't want Mac to be thinking of the next treatment or to worry. So I thought about cancer all the time.

"You're trying to take the pain away. A few times I felt like I couldn't do enough, or I didn't know what to do.

"Then you say a little prayer, get back up and go back into the fight."

Mac was suffering with a rare bone cancer called chordoma, which affects just 300 people in the US each year.

Gary - who described the MRI scan as "a monster grabbing my son's spine" - had already had the heartache of his wife Moira, 71, battling stage 3 breast cancer.

She has since recovered, but during her treatment they found out about Mac's tumour. His daughter Ella recalled: "Dad dove into the storm. Whatever's going on in his life, he goes full on.

"He did amazing, but it was hard to watch because it was traumatising.

"It's really a testimony to his character - he doesn't let adversity slow him down."