In what circumstances does or would your character drink alcohol? Left to his own devices? Never. BUT he could probably be talked into it by someone else if they were persistent enough and maybe used blackmail.
How much would they normally consume? Do they get drunk every once in a while, or live and breathe alcohol, or make sure to stay under the legal limit? Nothing, normally. Maybe if someone insisted over a fancy dinner, but otherwise he wouldn't really care either way for it.
How much alcohol tolerance do they have? Does even a sniff of alcohol knock them over, or can they guzzle alcohol without feeling impaired? Featherweight. Depending on the drink, he'd be more than tipsy after two or three.
What kind of drunk is your character? How would they act if they were drunk? Affectionate and philosophical. Though he'd be less-than-nice if you forcefully shoved him away from you instead of nicely shuffling him onto someone else.
Who would they go drinking with if they had to choose drinking buddies? Someone he knows, like Saix. Or someone who doesn't seem like they'd take pictures of him doing aforementioned barfing, like Itachi (how do you work camera when blind?!?!).
What's their alcohol preferences? Beer, wine, mixed drinks with fancy names? He doesn't normally drink, so no idea, but he'd probably prefer the sweeter or more interestingly-flavored mixed drinks, but the names would be eye-rollers.
Green alcohol y/n? As long as you took the first sip to prove he's not about to drink algae.
Your character is completely drunk. Who do they drunk-dial, and what do they say? Namine, to ask her if she could get some ice cream from the convenience store. And to get herself a flavor she likes, so they can eat it together and talk, because he doesn't discuss life matters with her enough. Though he'd probably just fall asleep at the table shortly after getting back.