Acute Indigestion. A good diagnosis.

My friend is having a problem where if he skips a meal for 2 days even once, he gets too sick. He starts vomiting and has 6-7 continuous vomits. This problem persists from last 3 years. Everytime he went to a doctor, the doctor would say, its food poisoning or normal indigestion and give him zintac or something like that. After eating in a routined manner he gets well. He stays in a hostel as he is a college student. So when he skips the morning meal for more than 2 days, he gets very sick. He starts vomiting with a lot of stomach pain. He can't talk or walk. He feels exhausted. Everything he eats results in vomiting. No loose motions are related, only vomiting happens. He becomes dehydrated and thus very lathargic. Noone is able to diagnose hus problem and he is very much in pain. Please suggest something. His mood gets very irritated due to this. Please, suggest a solution with a good diagnosis.