The former sportsman's brother Rahman Ali told Sunday's (03Feb13) edition of U.K. tabloid The Sun that the fight legend was "very sick" and could have just days to live.
He was quoted as saying, "My brother can't speak, he doesn't recognise me. He's in a bad way. He's very sick. It could be months, it could be days. I don't know if he'll last the summer. He's in God's hands. We hope he gently passes away."
However, Ali's daughter May May has hit back at the report, insisting her father is well and was looking forward to watching the Super Bowl at his home in Arizona.
She tells the Associated Press, "He's fine, in fact he was talking well this morning. These rumours pop up every once in a while but there's nothing to them."
Ali, who suffers from Parkinson's disease, celebrated his 71st birthday last month (Jan13).