In 1998, Ali began working with actor Michael J. Fox, who also had Parkinson's disease, to raise awareness and fund research for a cure.

"Parkinson's is my toughest fight," he said in a 2012 Esquire interview. "No, it doesn't hurt. It's hard to explain. I'm being tested to see if I'll keep praying, to see if I'll keep my faith. All great people are tested by God."