im not usre about the condition, but if you feel your not happy then ask for another opinion do not hang out waiting til your normal vet is about.. though usually a cat can be off of his food if he feels unwell. though you should try to wet his lips with your fingers with water on just so he doesnt become de-hydrated,. if like the other post says he could feel blocked inside thats the answer to him not wanting to eat….. the other cat is probably attacking at him because something is wrong. thats a thing all wild animals do they dont want a weak pack/family member.. you should try to keep them slightly seperated for a while. hope you get through to the vet, soon as, hugs x