L.D.
That is wonderful that you are making such an effort to include him! As a parent of a child with diabetes, that makes me very happy. For diabtetes, usually the parent needs to know the carbohydrates in the food so they can give the child the correct amount of insulin. As far as finding gluten free, most grocery stores have a gluten free section stocked with treats. I know Whole Foods does. I'd ask the parent because they probably already have a list of places they go. Good luck with the party!