It is fair for you to erect a boundary such as, " There is to be no alcohol in my home"... it's up to you to decide what you will do if that boundary gets crossed.
BUT...it's his home too? He is an adult who can choose to drink. That's his right. TELLING him he can't have booze in your home is a rule, not a boundary.
It's going to be difficult to maintain a boundary such as that while living with an active alcoholic.
My first real boundary was that I would not engage with XAH when he was drinking.