I have autoimmune hepatitis and then developed diabetes because of the prednisone. I see a nutritionist who has me on a carb restricted gluten free diet, because she said there is a connection between diet and autoimmune and that people with autoimmune diseases even if they don’t have celiac tend to be gluten sensitive. I can tell you that I have followed this diet for 6 months and when I do eat gluten, I feel more bloated, tired,etc. I definitely feel better without the gluten.
I am so sorry about your daughter. I have three kids and have had to deal with different issues with them as well. My suggestion always is that as mothers we have good instincts. If she seems better on gluten free then you should keep her on that diet.
I find most doctors are very focused on just pumping meds into to people and are not as focused on other aspects. My suggestion is to find a pediatric nutritionist and also a pediatric hepatologist – not sure who is treating your daughter.