Hi,
He may easily solve this problem from ever happening if he will take a small pinch of Epsom Salt with each meal and drink more water between meals when he is thirsty instead of any sodas etc..
If he will take an enema, this will clean his colon out and solve this problem, right away also but he needs to learn to eat and drink the foods which will provide good bowel movements.
His digestive system is not functioning properly and he may benefit from some good probiotics to introduce the needed digestive flora to digest what he is eating now.