The mucositis will persist for several weeks or months after treatment. Throat pain will persist and normal eating will take many weeks, since he is on a feeding tube, that might be left in for a while, those who have had one can advise. I am almost 5 months post radiation treatment. I am eating normally although things don't taste normal and still have some mucous problems and dry mouth persists. I just had a PET scan and am on a once a month doctor visit. This will be his life for a while, like years. Good luck.