Lightweight

The person who gets drunk without much alcohol consumption, ruins the nights of their friends because they are often pathetic and emotional drunks and lose any ability to function on their own after just one beer

Person 1- “look at Barry, what’s wrong with him?”
Person 2-“nothing is wrong, he is just drunk”
Person 1-“he is drunk enough to cry off of one beer? We have only been here for ten minutes!”
Person 2-“yea, he is quite a lightweight”