Update: my wife has gone to pick up Baker the cat and bring him home. The night shift vet says we should isolate him from our other cat for a month, but that's a non-starter. Other vets at the place have said not to isolate him. She's going to get clarification when she arrives at the hospital. Same goes for the type of food to give him (both normal and in his feeding tube), whether or not we need to take his temperature, and how we should fit his E-collar.