OK well in that case I would stick to a light diet > bland type foods and not heavy meals > starch type foods are easier to digest...(breads, potatoes, rice, soups, crackers, applesauce...etc..)
Have him follow up with his pediatrician tomorrow I suggest if possible..
Over the counter meds that may help nausea > Dramamine, Benedryl, Emetrol , Pepto bismol...
Any diarrhea? That would be common with a gastroenteritis but you did not say that he had that symptom...
More reassuring signs would be that abdominal pain is not ongoing... no fever.( especially not fever >102)
Red flag symptoms would be intractable vomiting where he can't tolerate anything/ abdominal pain so severe that he can't sleep through it , throwing up blood or coffee ground material , bloody diarrhea develops...
I hope that this is helpful for you. Let me know if you have further questions.
I will be happy to get back with you!
Anthony Bray MD