My husband throws up every morning & has been since high school. He is fine the rest of the day. If he sleeps late he has no problem.

Too many scenarios. There are many possible explanations for this phenomenon. Even though he seems well, there may be underlying problems that need attention. A thorough search for the cause begins with your family doctor, who i recommend you consult.
Low cortisol? Cortisol is a very important anti-inflammatory hormone secreted by your adrenal cortex. It is nature's prednisone. Too little cortisol can manifest as low blood sugar, inflammation, nausea , vomiting, anorexia and other symptoms your cortisol levels peak in the early morning. Maybe when your hubby gets up too early, his cortisol is too low and causes symptoms.