|It would be silly to think that just because he threw up, this would be enough to deter him from ever drinking again.
I agree, especially before he knows his limit and it can take a while to figure that out. Limits change too. When I was 16 I mixed myself drinks that were 90% alcohol and 10% mix and never got drunk, now 1-2glasses of wine and I'm tipsy or drunk depending on the day and how long it's been since I last drank.
I wouldn't necessarily be proud that he waited until he was 19 to get drunk, it's not something you'd write home about or put in the Xmas letter you know.lol I'd be happy he waited.
Getting drunk does not mean a person is binging either.
I'd talk to him about the reason he drank. Was is because his friends were drinking or is it the stresses of college. The answer would make a huge difference between whether I took it further or left it alone. At 19 you can't do anything, but if the stress of college is what caused him to drink then with a history of alcoholism he's on a slippery slope and you could help him find ways to deal with it other thank drinking.