Invite him to be a roomate and give him the murphy bed. Oh right you don't want to kill him...
Lots of bad potions in the game too either through ROM or the Scientist field. You can maybe buy them and hand them to him... actually haven't tried this on a spellcaster as I just zap them.
Lock him in a room with lots of angry pictures/items or sad ones. Put urns in his room so he cries a lot.
Take turns walking in on him when he's in the bathroom... you know so you're sims don't get as embarrassed.
Send him a bad bouquet with flower arranging... (age him up).
Send bees after him.
