Hi there. I’m sorry it took us a while to respond…I’ve been pondering over this since you initially posted. I think you may have to consider permanent separation. This is doable in a cat household, as you’ve seen, though it can be annoying, but it might be safest for the clowder.
I assume you’ve tried Feliway?
Hey there – because this is a potential emergency, I would call your vet. How’s he doing today?