fireflybob
In the UK there is already is legal duty placed on Doctors to make a disclosure contrary to the usual duty of absolute confidentiality where the Doctor believes there is a risk of death or serious harm to others.
I don't know what the policy of the medical authorities is in Germany is and their unusually strict privacy laws may mean that such a disclosure by a Doctor is less likely to happen.
53. Disclosure of personal information about a patient without consent may be justified in the public interest if failure to disclose may expose others to a risk of death or serious harm. You should still seek the patient’s consent to disclosure if practicable and consider any reasons given for refusal.
54. Such a situation might arise, for example, when a disclosure would be likely to assist in the prevention, detection or prosecution of serious crime, especially crimes against the person. When victims of violence refuse police assistance, disclosure may still be justified if others remain at risk, for example, from someone who is prepared to use weapons, or from domestic violence when children or others may be at risk.
55. If a patient’s refusal to consent to disclosure leaves others exposed to a risk so serious that it outweighs the patient’s and the public interest in maintaining confidentiality, or if it is not practicable or safe to seek the patient’s consent, you should disclose information promptly to an appropriate person or authority. You should inform the patient before disclosing the information, if practicable and safe, even if you intend to disclose without their consent.
GMC | Confidentiality guidance: Disclosures to protect others