Hi, and thanks for your query on eHealth forum!
If your husband does not have a stomach ulcer, acidity, H pylori infection or gastric reflux, then probably he has an epigastric hernia that is causing pain. The stomach or intestine bulge out through a weakening in the muscle wall. Please get a surgeon to examine this. Meanwhile do not lift anything heavy or push hard. It can be a referred pain from heart or lung, hence these need to be ruled out. Duodenal ulcer is another possibility.
Since a confirmed diagnosis cannot be given on net please consult your husband's doctor regarding this. Hope this helps. Take care!