Sorry, but had to jump in here. I have been sober since 1994. Any counselor that tells him that beer is O.K. is an idiot. The others are right -- he has to want it for himself. The cancer treatment right now is providing him with a great justification for his alcohol consumption. Threats will not work, but clearly delineating the expected behavior and consequences of non-compliance is entirely appropriate.

Wishing all the best for you.