He is an alcoholic. He'll drink this weekend one way or another IME. It doesn't really matter how you say it, when you say it, or how well the discussion goes.
Asking an active alcoholic to not drink for a weekend (that might be a bit stressful to begin with) is like asking a diabetic to just not get high blood sugar this weekend.
I finally had to choose if I wanted to do things with my active alcoholic, or without him. There was no way to do them with him, without the drinking.
I did that for a long time. I'm sorry. It is a sad spot to be in.