I was listening today to all these references, and while it's pretty clear that he partakes, I wouldn't expect that he has an "issue" either.
That said, I do think the fact that he's so open about it may be cause for future concern. I mean nicknaming a line of coke on a black chick's skin (No Church in the Wild) is pretty heavy haha especially for a topic so typically taboo in hiphop.
But still, I'd be shocked if he ever got to the point where it was a serious issue for him. It's pretty clear from how he talks about it that he LIKES it, but like you said, he seems fairly disciplined so I'd be surprised.