ANSWER:
If you are in a Muslim country, complain to the Muslim court and have them arrest her and discipline her. If she is in a kafir country, you can’t do anything as this is against their laws and you have no choice but to remind her of Allah and show her how bad this path she is walking. If she doesn’t listen, disown her and cut her off from the family and ask people to report her to the authorities! Make a lot of Duaa for her guidance but there isn’t anything more you can do!