D.B.
Before you go thru all the stress and invasiveness of testing and endoscopies and possible feeding tube, why not try a balanced food product, totally safe for children (it can even be given to preemies thru a feeding tube), that will most likely address this issue. If he's drinking Pediasure, he can drink this. It's called Reliv Now for Kids, it's made here in US under pristine conditions, is guaranteed, and has helped thousands of kids like yours. I can give you more info if you want. You can't get it in stores - it's sold thru distributors who will help you and connect you with other parents whose children have gone through similar situations. I can give you more info in about 15 minutes if you want to spend the time.