Hi DM-
Welcome!
When my fiancee first started with his treatment he found that eating an icepop will help sooth the pain and numb the area a bit. Icepops will also help hydrate the mouth. Oatmeal is good. Have you ever tried Cream of Wheat? Milkshakes are also a "nice" treat.
My recipe for Charlie:
1 banana
vanilla icecream
non dairy dry milk
and whole milk
This has a lot of calories as well- Charlie just finished his treatment on Friday, so he wont be eating thru the mouth for a while yet.

I wish you the best! Congrats on finishing treatment~
Delia
please let me know if anything helped- I will look further into good foods also.