He's definitely an alcoholic. There's no other way to account for that facial bloat.
I know it isn't said often enough around here, but Patrick is a dole-collecting bum who does literally nothing all day. It's a known fact that he frequently hangs around bars early in the day. He's almost certainly sipping beers from the early afternoon till late at night. He doesn't strike me as someone who goes nuts and drinks himself into a stupor, but rather someone who drinks steadily all day, every day.
I think it's just beers to be honest. Sugar doesn't have to be factor in it, this isn't regular weight gain he's having. I don't even think the variant of booze matters that much, but rather the way in which he drinks it.
Again, I think he's a "functioning" alcoholic in the sense that he doesn't go on insane benders but instead, he drinks it like most people drink coffee or smoke cigarettes. He's developed a dependence and he gradually quaffs a coupla road sodas spread across the day. He might get tipsy at the end of it, but the point is that he's got at least one beer in him at pretty much any given time. And that might actually be worse than going on the occasional bender.
I'm gonna go Dr. Steve here and point out that the thing with alcohol is that it's basically a poison that's just very shit at killing you. Going hogwild in the weekends and passing out feels fucking awful the next day because your body isn't used to getting a bunch of bad shit pumped through it. And that's a good thing. It's your body detoxifying in the literal sense of the word. It'd be very fucking bad if you reach the point where your body is not only desensitized to booze but actually used to it, dependent on it. Constantly needing to have venom coursing through your veins and never getting a break from it to properly recover. And that's exactly the point that pig reached a while back.
That's the reason why frat guys can drink themselves into an absolute fucking stupor 2-3 times a week for 4 years without turning into complete ghouls by the end of it. Besides youth, it's the fact that they take breaks between the binging sessions and actually do things. Counterintuitively, that kinda lifestyle is probably healthier than drinking comparatively milder amounts consistently, daily, for months on end. The difference between quickly moving your hand through an open flame and holding it right next to it for hours.
Think of the other alkies we know of. When did Lady Di and Ant really start to bloat up bad? They were always heavy boozers since adulthood, but the change didn't start to really set in until both of them got fired from their jobs. No reason to hold back on the day drinking afterwards because no responsibilities, coupled with a lot of free time to do it in. Pat's very similar but clearly not quite as exorbitant. It took him a good few years of neetdom to really start to balloon, and that ballooning's been ramping up over the last couple of years. Coincidentally, just after he crossed our path.
Remember child, no effect on his life.