I think he's hooked on something. But it dusent have to be drugs. The thing is that he is better of with out it. But he loves the feeling of it. I don't think there's anything suicidal about it though. Or maybe the only way to resolve it is to die. Cuz quitting it will be good for him but he will feel pain at first, but that pain might just be too much and he knows it. But if he keeps on being hooked to what ever it is, he just going to end up dead anyways, from overdosing.
I hope its easy to undersand.