All of that is nothing but rumor, innuendo and speculation.
What we do know is this. He was in heavy rehearsals and tech days for the big 50 shows he was going to put on in London. He was 50, and its been a while since he a) was in anything resembling great health, and b) since he has done 'the show'. So if he was doing pain killers and sleep aids, that's not far off track for such an endeavor. The long running joke in live theater was that the only tour with more drugs than the Grateful Dead was Cats. All that dancing, lots of pain pills.
After all, if nothing else, he was very aware of his star power, and stardom, and also knew that if these shows were not the best of his career, then by the time the first reviews hit the presses and the web he would have been 'a has been'. He was hemorrhaging money and knew it too, hell, I'd supposed I would need a sleep aid if I was owing upwards of half a billion dollars. So he had a lot riding on these shows, and I'm sure it was grueling. Rumor has it the rehearsals alone were costing $20 million to put on. Just exactly what is the rent on the Staples Center for almost a month? So I'm sure he was under a lot of stress and pressure, and I'm also sure that he was probably hurting like a mofo being 50, far underweight and having to perform like, well, Michael Jackson.