It's a proper mess of a story. There are claims he knew long before his diagnosis. His mum asked him years before his diagnosis and he said he didn't know, she said to get checked but he said he had to focus on his career. One of his previous wives also said he knew he had it years before and was joking with a journalist about it. His promoter and friend denies he ever knew about it, but wasn't 100%. He was hesitant to take the test that ended his career and only did so after his promoter told him to.
His widow is truly batshit crazy, but then so was he at that point. He believed he could teleport because one night he was in a really dodgy bar and he went to the toilet and then appeared outside. He didn't take into account the fact that his memory was completely gone and couldn't remember things from 5 minutes ago. He believed AIDS wasn't real because some book said so but the book was banned. His wife bought into all this, truly or financially I don't know, because ultimately she's been on a soon to be decade long crusade to get money out of the commission who banned him from boxing and took his supposed $40 million payday away. She also claims the commission supposedly removed his ban without notice many years ago or something like that.
When he was trying to make a comeback, and he did have 3 fights (one was MMA, isn't listed on his record but it was agreed that despite being MMA they'd use boxing rules, film was never released) he was told he'd need to do a test to fight, and he was given a specific location and doctor's name. The testing site required him to present ID and they where expecting him. He ended up going somewhere else instead where no ID was required (or at least they didn't know him, I can't remember exactly but ultimately it was not believed to be him who was tested).
Tommy claimed Nevada commission refused to provide him with his original test, they claimed they told him he can get a copy from the lab who did the test.
As far as his death goes, AIDS/HIV was never mentioned, but he was totally ****ed anyway. According to his wife he had surgery and they left a huge amount of tape in, it got really badly infected. He also had these messed up bicep and pec implants. She also claimed he got bitten by a spider and it was serious, and that while he was ill he fell over and hit his head damaging his neck. The sepsis from the botched surgery got him via organ failure, but it's not exactly surprising if he had AIDS. His mother said Tommy had said that if he was ever that ill he wanted to be left to die, not kept alive as long as possible by machines, and that she couldn't keep that promise as his wife was doing that. One member of his team/family, can't remember which, said she needed to keep him alive as she was British and needed to be married for at least two years to be allowed to stay in the country.
His mother, brother, and promoter/friend all agreed he had AIDs. His brother said he was injecting drugs into the side of his shaft so he could go for hours at a time, that must be how he got it. He refused every chance he had to prove it and made excuses every time, dying at 44. He accepted he had it at 26, when was not not mentally impaired (drugs, drinking, boxing absolutely ruined him). I refuse to believe that an athlete of his caliber and therefore financial worth would not have had a second test to make sure before announcing it.