WoW, I do not think that checking the background of the caretaker of a patient is the role of a doctor at all. It could be of a social worker, or a judicial officer, if we are talking about guardianship, etc. If the doctor has significant doubts about the mental health, criminal background, or any other thing of a caretaker it is not his/her business to investigate the caretaker. I think there may be a protocol o procedure (or a customary rule) for this type of case. It is the same in education and normally, in all countries you have that. On the other hand, I think this person did not follow his/her professional code of conduct. I do not want to trigger you to do anything, but if you happen to have a friend that is a lawyer, ask him/her about this case. In some cultures doctors believe they are above the rest of the human beings, and sometimes they assume police role.
I am in touch with psychiatry users and survivors that know a lot about discrimination and so on, I can ask them, if you want. You do not need to disclose your country.
OK, hope you are well. I would like to write a bad word about that doctor, but it is not permitted here. Sorry guys, it is upsetting what happened to Herethennnow