Thank you for your query.
I can understand your concern. Blood and mucus in stool can be due to a number of reasons. Though you have mentioned about colonscopy and test for celiac disease
you have not mentioned about any other investigation done on your son. I would first like to get the following basic investigations done:
1. Stool routine examination
2. Stool for occult blood
of whole abdomen
before jumping to any conclusion.
I hope I have answered your query to your satisfaction.
Wishing your daughter an early recovery.