Hello everyone.
I am asking for advice on how to deal with a friend to help her and not lose her.
My friend (let's call her Mrs. X) for the third time started a relationship with "love of her life" (henceforth called Mr. Y). Initially, I thought everything was beautiful and wonderful, but I have the impression that Mr. Y has a borderline personality. Mr. Y is making an X fights about a friend on Facebook. He reproaches her that she was already married and that he was not her first sexual partner. Once they plan a wedding and children, in a moment he says he has enough of her and he will leave her. After such situations Mrs. X is cutting herself not to deep). She limited contact with family and friends. She claims that there is no time because they are only for themselves, exclusive. She says she can not live without him and if he dies, she has no reason to live too. Apparently they have to be together all the time, always thinking about themselves. The friend began to suffer from lack of sleep. When we meet she seems very tired and with the luck of energy, behaving like a zombie. Mr. X also have problems with alcohol (he drinks almost everyday). When someone says to her that it must be toxic love she gest frustrated, starts cursing and defending Mr. Y.
They don't want counselling.

I am worried about her life and well being. What should I do? I have a feeling that the more I push the more withdrawn she becomes.