Had a friend who needed a place to stay for a while.
After I came home 1 night and saw he had not even put out water for the cats, I told him that it was not working out and that I had long ago dealt with alcoholism in the family and could not deal with it again. I think he chose to see it as more "my problem" than his, but he did move on, nevertheless.
On the other hand, I have a neighbor in our condo. He is a classic hippie from the 60's who did way too many drugs back then. I have learned with him that it's often best to proceed cautiously with people who overdo either drugs o r alcohol. Some days, he can be very affable. Other times, he can get extremely hostile. I had asked him to please put his trash in a bag and not just throw it down the trash chute because of the smell and unhygienic conditions that can cause. Well, he totally flipped out at me and I was really frightened for my safety.
So, if I were you, MRD, I'd just proceed real cautiously. Sometimes, minor things can set off people who overdo drugs and booze. Be careful.