It just begs the question about just what sort of trauma he's had in his past that makes him drink like that. Even when he's not "performing" with furries, he's still knocking them back. He used to bring his parents to show off his furry conventions, so maybe there's some element of him "not being good enough" in their eyes. Or it could be, he's just a real asshole when he's not drinking. I know he's moved from place to place, and normally people with good friends don't just up and do that, so maybe he's got a lot of skeletons or something.
Or he's just an addict and booze is cheaper than heroin.