Yeah, why even bother bringing up the alcohol really. You've decided you don't want this, it's your business and bringing up his problems will only make him start to get on the defensive and a defensive alcohol usually then goes on the attack and turns things around, confuses and confounds in order to get you to do what he likes. If you keep it about you, then you will avoid this sort of unpleasant interaction that with most alcoholics is unwinnable.