I have two feral cat brothers age 4 years, neutered males that have been together since birth. Sumo and Bonzai. Sumo is the larger cat and has always been the more dominant of the two and they have always gotten along well. Now, the normally submissive and much smaller cat, Bonzai has become the aggressor and Sumo has been hiding under our bed for a week or better with very little time out of there. We have taken him a food and water bowl and put a litter box in the room where he is for now. He has lost a lot of weight and is apparently still scared to death of his little brother. Please help!