Hi thanks for contacting a health care magic.... Here you are having stomatitis like inflammation with problem in gastric digestion.... Give him pentoprazole tablet for 7 days. Advise him to take more fruits..... Blue berry , avocados , kiwi good fruits for his condition.... Beet roots can be taken.... Drinking lots of fluid..... Chamomile in green tea can be given. If bloating more to relieve constipation you can give him psyllium like bulk forming agent in milk.... Onion , cabbage , cauliflower , turnip like gas forming foods avoided....for few days. If still no benefit usg done and consult gastroenterologist. Take care. Dr.Parth