The first thing that strikes me is his complete disregard for his position in his job. I could be wrong, but I am fairly sure that it is unethical and very wrong for a medical professional in the sort of capacity that he is, to be involved with a patient (I know you are the mother of the patient) but I would still say that him pursuing you is completely against the rules, even after you have been signed off from him.
Having said that, I think the best thing you can do is to keep away, have no contact, do not go looking him up on facebook, or his family, or have any connection to him at all. Stop speaking to him, and do not be any part of his life.
You dont owe anything to his wife. That is his responsibility, not yours.
You havent slept with him thankfully, so consider that a lucky escape too.
Your friend is not really much of a friend either, and it sounds more like she would just enjoy sitting back and watching some fireworks.
You did the right thing by ending it.