Ah, thank you for saying that!
Yes, my daughter and I have seriously considered communicating with her. Our compassion causes us to feel compelled to act. I have followed and watch Dr. Ramani (her videos). If you don't know, she is a therapist that focuses on narcissistic behaviors and relationships. I chose to accept her advice of investing in our lives and filling it with happiness.
My ex still spends energy trying to hurt us. He formed alliances with my mother and family members and the neighbors whose houses are next to mine. That is control and trying to isolate and cut me off. Staying out of his toxic energy field is one view. Having him tied up with the relationship with her keeps him away from us more. And he would never be without a woman, so there would always be another.
I believe that he has spun such a story that she would not believe anything we could say.
However, if at some point she or someone concerned about her came to us, we would be open to speaking to them.