I thought he was probably dehydrated. Soooo important. Maybe when he gets some fluids in him he will realize how much better he feels. One thing our RO did was put Kevin on a preventative script of Diflucan. It seemed to keep any mouth infections at bay. He still had the sores and used a ton of the magic mouthwash, and rinsed constantly, but he didn't get infections as bad.
I'm so sorry you are having such a hard time with this. It's different for every patient. Try to be patient with him, but, good job calling in reinforcements!!
Kathy