How can I get access to mental health services for a dangerous family member who refuses to see a doctor?

My question is, has anyone helped a family member to get mental health services in the home without having the patient themselves walk in to the centre?

A family member (30) has OCD and Paranoid Personality Disorder. Completely in denial of this. She has been sectioned for it in the past but they let her go because she had her medicine. She immediately stopped and has once again become dangerous.

Her paranoid thoughts accuse the sibling (19) and single mother (60) she lives with of very horrific things that aren’t true. But she believes them and acts upon them by mentally and physically abusing them daily.

Neighbours call the police regularly but are told by this person that everything is ok and that is enough to have them leave.

The police have been useless, GP makes a referral, but only one that this family member to physically turn up. And she won’t. The system is so messed up. HOW can I get her some help?