That's difficult to say
His family is hinting at suicide and that could be a possibility.
He was probably depressed because he wasn't doing so good from the health point of view.
He was trying to quit drinking but wasn't able to. He kept going back to drinking.
The sadness is even reflected in the songs.

So wake me up when it's all over
When I'm wiser and I'm older
All this time I was finding myself,
and I
Didn't know I was lost

Or maybe they're just lyrics of another song and don't mean anything.