Thanks for writing your query.
It seems that the boy is suffering from gastrointestinal infection
and the symptoms seems to be due to dehydration
as a result of vomiting and diarrhoea.
Care should be taken for his hydration. He should be given Oral Rehydration Solutions if on examination he is found to be dehydrated.
Antacid like Ranitidine 2-4 mg/kg can be given twice daily along with Domperidone
0.25-0.5 mg/kg thrice daily will help in curing the epigastric pain
Antispasmodic like Dicycloverine
can be given S.O.S. basis after meals.
Medicines to be given nder medical supervision only.
Get his stool examined for Routine/Microscopic and Culture/Senstivity and give antibiotic/antiamoebic according to the reports.
Also take care of his urine output.
I hope this is helpful to you.