I think, perhaps, you are misunderstanding what constitutes a boundary (among quite a few other things).
A rule is "You will not drink".
A boundary is "I will not live with an active alcoholic. If you continue to drink I will X" X being a consequence such as leaving or possibly an intervention. Nowhere in that is there any attack on the agency of a grown adult to make their own choices, however healthy or unhealthy they may be.
It's a bit painful for me to see my pre-recovery arrogant self in these posts. I don't think I ever went so far as to pre-screen my ex for alcoholism (or any other ism) just so that I might draw up a plan to save him from himself, though. That came later....
You do realise that a) what he is doing is legal and b) you can't save your loved ones by saving this man.
Do you have therapy and supervision as part of your course?