It wasn’t confirmed. It was speculated.He didn't have AIDS. It was speculated that his skin issues came from the removal.of his appendix and heroin drug use. It was never confirmed he had AIDS. He did od via speed balling: Coke and Heroin.
Edit. He wasn't poor at all too. He had so much money he was giving it away to bums on the street.
However, after going to an art exhibit recently and seeing what’s considered art, some like Basquiat from the same era in the south, it was just drug-berrish.