Does my daughter have Celiac Disease?

My daughter is 15 and has vomited once a day for her entire life. Last fall, it increased to three times a day,. The hospitals tests have found all body systems to be normal, no acid/bile reflux or gall bladder problems. She has tested negative for celiac disease with the blood test, allergy tests are negative, and food sensitivity tests are negative. She tested positive with a biopsy for Celiac Disease. Her GI doctor is not convinced she has Celiac Disease. Primary doc thinks she has more sensitivies although she tests negative. She has been on a gluten-free lactose free diet for 7 weeks and still vomits 1 or 2 times a day (could be changes in summer schedule). There is no correlation to what she reacts too. She eats eggs one day and vomits them the next, same with potatoes. She is supposed to continue the diet for 5 more weeks, have a second endoscopy to see if there is improvement, and if not, have a flundoplication. Diagnosis "excessive vomiting". The doctor sees no reason to test her brothers, even though one has a weight gain, gas, rash on elbows (5 yrs) diarhea (11 yrs. old) and the other has weekly migraines, (18 yrs. old) Any suggestions?