Thanks for your query.
Your son is having acute gastroenteritis
which is mostly viral in nature and takes few days to settle.
I advise you to give oral rehydration solution after each loose stools,give coconut water,curd.banana,.khichdi. Maintain proper hydration.
For fever five paracetamol
6 hourly if fever is more than 100F..
for 2 to 3 days,but i do not prefer antibiotic.
In case symptoms persist get him examined by a pediatrician
Wishing your son good health.