Hello dear
Warm  welcome to Healthcaremagic.com
I have evaluated your query for  your  grandson in details  .
*  Guidelines for better  outcome
-  Allow him plenty of liquids .
-  High fiber diet with plenty of green leafy veg , whole grains , cereals ,
    legumes , pulses , organic  fresh  fruits .
-  Avoid all types of junk foods , dairy fat , commercial  beverages , spicy ,
    non veg  totally till recovery .
-  Laxative  as  
lactulose  monohydrate  , digestive enzymes  prescription is
    mandatory  with  his  
pediatrician .
-  Check  that  he is chewing  his  food thoroughly .
-  Make  him  more  playful .
Wishing your  toddler   fine recovery .
Feel  free  to ask any further doubts .
Regards  .