Thank you for your question.
I am Dr. Su S. and I will try my best to help you.
I am sorry for his symptom.
In case of severe diarrhea, it is safer to get examined in ER.
This will prevent complications, dehydration.
Early start of treatment is necessary.
Meanwhile, please keep him hydrated.
Urine output needs to be watched.
If it decreases, it would suggest dehydration.
I hope this information will be helpful.
If you have any query, please feel free to ask.
If you are happy with my answer please click on the Excellent/Good rating.
Wish him healthy life.