What about crating him over night and when you are gone?? That would be the simplest solution to the entire ordeal. If I didn't want to lose my cat because my husband said he must go (and there's an issue I won't go into on this thread...) I'd find a way to keep him confined when he's not able to be watched.

Get a foldable dog cage, put in his litter box and some water and a little food for over night and when you aren't there, and put him in it.

Better a caged, not so happy kitty, than no kitty at all.