Hi, there. I can really feel for your friend because this same thing was happening to me - and I'm just 40 years old!!! Talk about humiliation and wanting to hide away. Anyway your friend needs to be evaluated by a doctor to rule out serious digestive disorders that can cause explosive bowels.
Is this a new condition? Does it happen daily or under certain conditions? It is impossible to advise what would help her without the doc diagnosing her first. After years of this problem, I finally found out about Colestid (prescription drug) which helps bind bile and form stools. However, it's not the right cure for everyone, and only a doctor can determine what she needs.
Tell her the fear is worse than the actual answer. At least with a diagnosis, she'll find some help. If she continues to not eat, not only will she hurt herself nutritionally, the body will begin to react negatively to anything she does eat, and her bowel problems will only get worse.
Good luck to her,
Katie G