<<Disclaimer: Verify this information before applying it to your situation.>>

My husband had horrific mouth sores, ulcers prior to his diagnosis with CD.
Once on diet for a few months they all healed and now if he has environmental
gluten issue he can develop mouth sores.

Have you eliminated all hidden, less obvious forms of gluten from your diet
and environment.  Maybe you are sensitive to even dust (sheetrock dust,
plaster dust has gluten sometimes)  doing any home construction/remodelling,
or is there even airborne flour (family cooking with real flour products?)

I also have 2 children who have diabetes, and one more who has celiac.