Nasty bug giving stomach cramps?

A heating pad will ease the cramps, but do not let him sleep with it on as they can burn the skin. A towel soaked in hot water and sealed in a zip type bag would work to fall asleep with. I do not think a 10 year old should be having cramps like this for so long, and if he was mine, I would take him to a doctor's office that sees children if possible to see what is going on.