I have a friend who is involved in a Haraam relationship

Q: I have a friend who is doing the Alima course. It is her second year which is about to end. She is studying the Deen of Allah Ta'ala but at the same time she is in a haraam relationship i.e. she has a boyfriend. I am  her close friend but I don't know what to do whether I am meant to carry on talking to this girl because I am no one to judge her as Allah Ta'ala is the best judge. But at the same time I feel that me being a friend and carrying on speaking to this person, I don't want Allah Ta'ala to ask and take me to account on the day of judgement for being able to do something. What should I do? I have tried so much to persuade her but she doesn't listen. As a muslimah what do I do?