What is his diet like. You should look at that. No sugar, lots of fruit and veg. Lots of water, lots of excersise. Set a time for siting to try and have a bowel movement. There are most likely lots of reasons for this general make up diet, fear of BM or getting in trouble. If you ignore something long enough you get good at ignoring it. Don:t take it personally just work the solutions, do your best to not get upset, don:t ask inform it is time to use the restroom, sorry you do not like the food but thats what we are having. When was the last time you saw the skeliton of a child when there was food available.
My 6 year old had that problem when he was a baby, they did a lower GI test on him and it showed a flap in his bowels wasn't working correctly you should talk to your doctor about doing a lower GI test on him, best of luck to you and you son, will be praying for you
This Forum does not address medical conditions such as your son's. Our focus is on developmental, emotional and psychological functioning and on issues of parenting.