Hi
Fever,
vomiting, loose stools- its likely that your son has a gut infection- which is mostly viral.
For fever, you may continue with
paracetamol in right dosage according to his weight given thrice or four times in a day.
If he keeps vomiting again and again, its better that you have him seen by a
Pediatrician. He might need medications like Domstal/ Onden for the same.
Loose stools will take atleast 4 to 5 days to settle.
You can give him probiotics like
Econorm sachet about 1/2 sachet twice a day for 3 days.
See to that he drinks well and passes urine atleast 4 to 5 times in a day.
Give him plenty of fluids like plain water, ORS, vegetable soups, porridge, coconut water etc.
Give him rice based food, banana, boiled potato, curd in plenty.
Give him small and frequent feeds.
At any point of time if he has high grade fever, he is very irritable/ lethargic, you see blood in stools, his urine frequency is less, refuses to drink- please do not hesitate to visit your Pediatrician.
Hope my answer helps you.
Wish your son a speedy recovery.