Seems like you grandson has been disgnosed as ADD (
Attention Deficit Disorder) thatl is why he has been prescribed
Ritalin. The test you performed on identifying allergies will give you a better idea on the childs allergies and allow you to avoid these allergens.
The lack of concentration and
restlessness are signs of ADD. Children of ADD commonly show these signs during their pre-school age. YOu will need to to consult a child psycologists for better management of the child.
Most ADD do resolve once the child grows older and undertands his area of interests. Till then try and keep the child withe what interests him.