An alcoholic cannot drink, period. That's not negotiable. However, he is an adult and can make his own sh*tty choices if he's so inclined. Asking you if he can drink is basically his way of drinking guilt-free because YOU said he could. But then he'll drink anyway because YOU said no and that was just too much for him to handle. Typical dry drunk bs. Honestly kiddo, I'd mentally prepare myself for relapse if I were you. He's already said he won't do forever, and that's the only option for an alcoholic to recover. What are your boundaries when he starts drinking again?