A-lot of bones are in the human body
Well I'm just shooting in the dark for the obvious, but they must be careful that the patient doesn't depend on them too much. Although you're a therapist to help them, you need to walk a fine line so they don't always come to you for help and are able to do their own decisions. I'm sure it wouldn't be a bother to help them every now and then to help them make their own decisions, but there'll be times a therapist can't help (or opinionate) or simply believes that the person can work it through.
If I were the nurse in this scenario, I would probably go over a lot of key parts of development and how they work. Also, say that most if not all developmental phases are painless, which may help her worriedness. Hope this helps! :)
Answer:
because it is where they are dominated
-to eat only when you're hungry .