HELP!! Is she crazy or is there a deeper problem beneath the surface?

[Ntokozo]

Hi, I would like help to find out what type of person would firstly believe that when she drinks and dances she is possessed by evil spirits (Demons), she has multiple sexual partners, posts on social media that she hates her father and wants to kill him because he allegedly abused her mother before she was even born and that there is nothing she hates more than coming back home from college during holidays.
Most recently accused her sister’s husband of attempted sexual assault, when he is adamant that he did not do it, and in turn has resulted in a strain on their marriage because of the husband emotional and psychological damage over these accusations. Her mother is oblivious to all of this and she believes her and thinks there is nothing wrong with her daughter and that has broken her relationship with her married daughter. I am a very close friend of the couple and I would love to help but do not know how. They are the best of friends and most loving people I have ever met; it would pain me to see them lose each other over something like this.
Concerned friend