Linda, I can't speak to the Erbitux but I do have firsthand knowledge of radiation damage. Mine was quite severe, my mouth and throat were full of sores and my skin quite burned around my neck as well.

For the former, my experience with viscous lidocaine was a positive one - insofar as it was about the only thing that would temporarily numb the pain enough (and it really didn't do a great job, just a passable job) for me to force down a couple of bottles of liquid nutrition. Not a ringing endorsement I know, but it might be something to ask about.

For skin burns I recommend silver sulfadiazine. I'm assuming it's called the same thing where you live but you can always check with a pharmacy. Great stuff for when the thinner topical creams don't do the job.

I hope your brother begins to feel better. He's going into the really tough time, the last weeks of radiation and then the few weeks afterward that are often just as bad, even a bit tougher unfortunately. But he will get it through it and it's wonderful that you're there to help him. I wish both of you the best, and please keep writing.