What do you do with a stubborn senior?

Here is the story in brief (I hope); my father-in-law has dementia. He has always been the type to be very "the man in control" so this has exceedingly been difficult. The last couple years he has been drinking. A care provider does come in the home which is helping. Recently we took away the alcohol leaving only a little wine. A family friend is helping in the yard and he wants him to go buy him some brandy. The friend knows that we just took it away but now Dad is going to walk to the store and get it if know one buys it for him. It was not that long ago that we took the car away, which actually he should not have been driving for a while. Then someone said we could let him have beer but he is not a beer drinker, he wants his brandy. Physically he is fairly healthy and he will walk to get what he wants believe me! So any suggestions?