Good luck with the radiation. Maybe they can increase the pain dosage or switch to another, everyone reacts differently to them. His symptoms don't sound that unusual. It's tough treatment to go through, and was like that myself my last round, and was by myself. All I can say is keep the doctors abreast, to treat what you can, since he is being hit all around by several means, and conditions, like the mucocitus by brushing the teeth after each meal, rinsing, flossing. Some like a water pic, treat bacterial, viral and fungal infections, like thrush, but can also be a combination of either, dry mouth. Adequate nutrition, hydration, sleep, which is all I wanted to do, which is not a bad thing to do, neuropathy from chemo. Some radiation facilities spray your mouth to cleanse it out, daily, and hydrate you with IV fluids.

They say, you can have the best medical care in the world, but more importantly is the support you have, during, after treatment that matters, which seems like you are doing a good job with.

Hang in there, all this shall soon pass.