If your interested I would check out the book Restoring Your Digestive Health by Jordan Rubin. N.M.D. and Joseph Brasco. I would also investigate Water Kefir. We used both to cure our son of Acid Reflux and other allergies since birth. My wifes Aunt was able to vastly improve her digestive issues as well. Kefir does a great job re-populating the good bacteria in the digestive track. Go for the real deal, not the powder stuff. We also make Milk Kefir, but that may not be what your child will tolerate now that's why I recommended Water Kefir. There are a couple of great forums out there for you to research, Dom's out of Australia is one that comes to mind. Good luck, I know how difficult it can be to see your child suffering and feeling like you don't have any control over their wellbeing.
You'll never see the light if you're in someone else's shadow, or said another way, life is like a dog sled team, if you're not the lead dog, the scenery never changes