sc nailed it--we don't have that much power. You're still looking at this in terms of how what you do or don't do (or say or don't say) will affect his ability/inclination to choose recovery.
There are a few things we do or say that CAN make matters worse (enabling being probably the biggest one), but apart from avoiding doing those kinds of things, whether we drink or go to meetings with them or counseling with them or anything that looks like "support" really doesn't amount to a hill of beans in terms of getting someone else to the place where they are motivated to quit drinking.