Latest news is that it was probably an overdose on sleeping pills - hopefully it was accidental.
There is no such thing as an “accidental” overdose on sleeping pills really. You need a massive overdose (think: 50 to 100) to kill yourselve.
That would depend on a lot of things, actually.
They could be extra super-strong pills, and he accidentally took as many as he would if they were regular ones. That’s doubtful, but a possibility.
He could have taken a whole handful of them, thinking that he really needed to get to sleep but would have a hard time doing it.
He could have had a lot of alcohol first, and then taken the pills. The alcohol would boost the potency of the pills, especially if he was really drunk and forgot how many pills he’d already taken.
Yup, he was on Stilnox. Apparently known as Ambien in the US. Has some side-effects (including sleep-walking) that’s caused the Australian Adverse Drug Reactions Advisory Committee to put the stuff under review.