I had a friend in alanon 15 years ago whos husband could not drive. He use to walk almost 2 miles one way to get to the liquor store. She wouldn't buy anything for him. She had no idea how he was getting it as he didn't work and she was gone each day.
She came home one day and he was dead. The majority of the people at his funeral were alnoner's. Sad, but happens all the time.
Your boundaries are not buying alcohol. You need to always follow through, or he will know that he can work you and always get what he wants.
Hugs my friend, life only gets worse with an addict.