Hi,
Welcome to Healthcaremagic.com.
I had gone through your question I can understand your concern.
As per your history it seems to me he is suffering with reflex
esophagitis (a condition where stomach acid regurgitate to
esophagus or even throat too).
It can be because of gastric ulcer too because food aggravated gastric pain is a cordinal feature of gastric ulcer.
It can be treated with some life style adjustments and medication like :
Avoid oily, spicy and junk food, take dinner two hours before sleep, avoid late night foods and rais at least 4 inches of his bed (head side) to prevent regurgitation.
As I don't know the proper weight of your child I cannot directly write the dosage of medication but if I would have been the treating doctor,
pantoprazole is good option for this condition.
Hope my answer will help you and you can write to us further if you feel any more clarification.
Regards
Dr Muzaffar.