A friend of mine drinks rarely, maybe 4-5 times a year, but when he does, goodness me.
He'll be having a great time, life and soul. Lively, but no more so than anyone else in a group that's also been drinking. Talking fine, walking fine etc.
Then all of a sudden, he'll become properly plastered. Can't stand, talking nonsense. He doesn't turn nasty, but he is a liability for anyone who's out with him, and getting him home safely becomes a challenge.
He always goes out intending to have a couple and no more, but he never does, and as I say, he only does it rarely, but is the only answer for him to not drink at all?