did you doc tell you about the BRAT diet.
If your son has a stomach virus he may not have any dairy! sounds like he's getting milk before bedtime. NO DAIRY! Very important.
Well, as far as the BRAT diet: B is for bananas, R is for Rice, A is for applesauce and T is for Toast.
Water and Gatorade should be the only thing he drinks.
Also, there is a over-the-counter vitamin (i guess it is) called Probiotic Acidiphilus. It is actually a bacteria but the kind of bacteria your digestive track needs. Just open a capsule and sprinkle half of it in either applesauce or in his gatorade.
He'll be all better in a couple of days but keep the Dairy away from him for like a week to make sure the bad bacteria is definately out!
My son gets these viruses every few months thanks to Daycare. I know these remedies all to well.