Chev,
What rules did you give him?
Is he following your rules?
Do you trust him that he is following "your" rules.
How long do you think he will follow your rules?
Hon, he is an alcoholic and "rules" don't apply to alcoholics. They do what they want when ever they want with out any consideration of loved ones in their life.
If you are calling these "boundaries" I think you are confused. Boundaries are for us, not rules for them. Boundaries are ... I will not call him in sick if he is hung over. I will leave him drunk on the floor if he passes out and not put him in bed. I will not engage with him when he is drunk and will leave the home. He is a drunk and drunks need to drink. By you threatening him with your rules is not going to make a bit of difference. He will sneak around and lie to you, that's what they do best.
Imo, You need to start taking care of you and not making up rules for a grown man. He is an adult and can legally drink himself to death. I am sorry, it sucks, but they do have that right.