What Causes Frequent Bowel Movement After Overdosing On Doxepin?

My husband who is bi polar overdosed on doxipen in February. Now he has had a foley since and also now he is having frequent peanut butter like stools and does not know when they are coming. He is in an Assisted living as he cannot empty his foley bag and has shaky hands and when he gets up has trouble balanceing. He uses a walker but does not want to walk much. Sits in a chair most of the time. Has had depression and the doxipen was given to him as a sleeping pill. He looks well and talks well but is so embarrased having to have help cleaning up after an unexpected bowl movement and has no feeling it is coming. His depression is much better but he sits all the time. Does goes to Breakfast, lunch and dinner. The frequent bowl movements are hampering him feeling better as he is afraid to leave his room as he doesn t know when they are come on. Can you help me help him. He had a colonoscopy a year ago in July however he would not be strong enough to go through the prep. He is eating but has lost his taste.