And he would request all you have... like many apps do today ( in case of permissions)... and refuse to provide service if not given all.
Passively snooping on health info you have no business looking on gets health personnel sanctioned regularly in the present system. It would be even more risky if they actively had to ask for the information they didn't need.
Of course, for medical information there often has to be emergency overrides because you might need immediate help and you (or your designated trusted person) might not be accessible and capable of giving active consent.