Put your son on a completely organic diet for about 3 weeks. Eliminate Sugar and other sweeteners. Eliminate as much flour, corn, soy, eggs, canola oil and meat as you can. Eliminate foods that are processed and in boxes and cans. Feed him stewed apples for breakfast with some cinnamon. The apples need to have their skins on. Cook to a chunky applesauce with a little water. Give him lots of filtered water to drink.
If after 3 weeks of the apples and the organic diet and there is little improvement, then explore the possibility of parasites. The pictures indicate an impaired digestive system, not parasites.
Our food system is highly contaminated with pesticides/chemicals.
The amount of contamination has increased dramatically in the last ten years and it directly affects the digestive system.