He's 21 Now

[JJJ]

Janet I'm sorry your going through this. But his 21 and trust me he will regret drinking when he wakes up in the morning

I think that most of the young ones that don't go drinking on their 21st birthday are depress at home for not having anyone to party with. Or worst they've been drinking at a younger age that drinking is whatever to them (not everyone).

I would just tell him that I hope he had a great night and to always remember that you are willing to pick him up if no one is sober enough to drive.