Asperger Syndrome and bowel movement

My son is 15 years old.  He has asperger syndrome.  My son holds his bowel movements for long periods of time.  It get encrusted on his underwear.  Small balls of bowel movements falls down his legs.  He smells most of the time.  This has been an ongoing problem since kindergarden.  We have tried mineral oil and other meds from the pediatrition.  When he finally does go it is such a big mess for days at a time. (diarhea (diarrhea))  He goes back to holding himself.  I am afraid of long term problems from this habit of his.  I guess I just kept hoping the older he got he would overcome this habit.  Personal Hygiene is another major issue with him.  No showers, no brushing his teeth, no wearing clean clothes, refuses to get his hair cut the list just goes on and on.  Its very frustrating.  How can I make his brain understand that he needs to use the bathroom?

[jlee30]

Been there and done that with our now 20year old son.  Strategies regarding BMs that we have found successful:  1. increase in daily fiber - its been a challenge to find an acceptable foods with this stubborn 'child' but he has always liked apples SO 'an apple a day...'; 2.  daily fiber tablets - he takes one Benefiber tablet three times daily; 3. lots of fluid - mostly water or unsweetened colas/iced tea - no fruit juices because they are sooo high in sugar; 4. routine,routine, routine....our son has been allowed to take whatever game/book he is involved with into the bathroom with him because he gets just BORED sitting on the toilet and won't spend the time fully evacuating his bowels - allowing him distractions has helped. Patience on our part is required.  This has been an issue since childhood and these strategies have helped.