Hi,I had gone through your query and understand your concern.
Your son has most likely been suffering from acute watery diarrhea
due to viral cause.You need not to worry much because viral diarrhea is a self limiting disease and it will be resolved spontaneously within a short time (usually less than five days).
But please continue normal food as usual and give oral rehydration solution (ORS>about 100ml) after each loose motion
If any signs of dehydration
like sunken eyes,irritability/lethargy
, excessive thirst etc appears,blood goes in stool or vomits everything,then please meet you local doctor.
Hope this helps you.If you have further queries,please do not hesitate in writing us.
Wish your son rapid recovery.