The only things that can be done are to either:
- have him leave, get adopted by someone, and adopt him back (as then he'll remember being yours, but will come back in the good house)
considering how fast nook sells the plots of land when someone leaves, would this even be possible to pull off easily?
i think one thing this game does not do well AT ALL is villager rotation. its nearly impossible to get someone to leave if you don't like them. and if you get a random camper you do like, you have to pray that the random villager they want to replace isn't someone you like. its so nutty. with so many villagers in the game, itd be nice if they could more simply move in and out.