I don't think that's the case at all. He drunk at some points and took drugs at some points but never 'partied'. If you read his book it gives a bit more context.
Not what I'm saying. Partying suggests something very different to what he experienced. He's also been sober for a long time. A relapse is possible but so are a hundred other reasons. Suggesting it was his own fault is quite grim.
It's likely, given his history. At the same time, this is a silly argument. Even if he were still alive he wouldn't care what either of us thinks, so let's not waste any more of our breath on this.