Let's get a few things straightened out.
1. She is not legally incompetent, correct?
2. If #1 is true, then you're basically stuck - you can't force her to get help and you can't force her to stand up for herself.
What is perhaps the critical point though is that you said she has two specific mental issues which can cause the patient to have difficulty discerning truth from fantasy.
You certainly can't force her to seek psychiatric help - or indeed, any sort of help. There is literally only one option for you and that's to contact law enforcement.

