Eclectic Gastroenterologist recommendation needed

My husband has really hard time with his belly and some times he cannot eat for days in a row. Even if he eats a little bit, he feels bloated, and feels something hard in his belly. He has been dealing with these issues for years (as he has genetic predisposition for it), but it seems they are getting worse with age. The doctors did ultrasound, including endoscopy. Everything turns normal, but he feels miserable. Of course, his symptoms could be due to stress, but he is trying to have a better recommendations from doctors besides sleep and eat healthy (we cook meals almost exclusively at home from organic ingredients). So, your recommendation for a doctor that can see beyond the tests, and hopefully provide a medicine/strategy to help him, would be greatly appreciated. Also, if you are aware of European Gastroenterologist in Bay Area, please share the name, and we will also consider this (as my husband is from Europe).