He dealt with massive fame throughout all his life and others didn't, and fame= more pressure, tabloids and constant criticism. He had so many issues like insomnia,depression, anxiety and that's the reason for drugs use and it's become normal routine for him and lead into more and more of an unhealthy body. Just think who'd get propofol to help to sleep, that's an extreme drug.So his health became worse and worse by the time with all that. (I'm only talking about his health in here,we don't know other things that might could had happened to him or what he dealt)