Hello minlari, and welcome to NeuroTalk. I'm sorry to read about your son's problems, and I hope the information below might help you in some way.

It surprises me that the Gastro-enterologist didn't order a gastroscopy, seeing your son has such a long history of vomiting.

One condition which could cause this vomiting is narrowing of the esophagus. That's the food tobe that goes from the throat to the stomach. Narrowing of that tube is fairly common, and can cause this type of symptom.

Another one is a hiatus hernia. In that one, part of the stomach actually sits in the chest instead of under it, and because it's only a part of the stomach, the lower bit is half blocked off. So..... when a person eats, the top half of the stomach which sits within the chest cavity, gets full very quickly and once over full, can lead to vomiting.

These are only 2 suggestions that might be causing your son's problem. Look them both up on the internet and see if either of the symptoms suit your son, and then make another appointment to go back and see the Gastroenterologist, once you're armed with further questions to ask.

Welcome again, and I hope this has been of some assitance.