Thank you for your query.
The doctor has advised the right food for your son. You can add bread, potatoes, over-ripe banana and lots of fluids in the form of lemonade, buttermilk, coconut water. However avoid fruits and fruit juices till the diarrhoea
It is advisable to discuss with the doctor and get a stool routine examination done to know the possible cause of diarrhoea. Thereafter appropriate medication can be started.
I hope I have answered your query to your satisfaction.
Wishing your son a speedy recovery.