How Can severe Stomach Upset Along With Vomiting Be Treated?

Hi, my husband has been having upset stomach off and on for several wks. For past few weeks, if he eats much of anything solid, within minutes, if not seconds, he will throw it up. No blood. Had gallbladder removed 18 months ago and had identified couple of things he could not eat after that. This is pretty much anything. Liquids do not bother him. He s 72. Regular checkups and bloodwork. Takes heart meds for controlled arrhythmia. Barrett s esophagus was diagnosed on endoscopy couple years ago, but seems that no real stress what put on it. He has looked that up but doesn t feel it is the problem. Ideas?