FYI  Contact the police and request information as to filing a petition for her to be held on a psychiatric hold as she is a high risk to do harm to self or others. Two people petition, even better. She can then be held in a psychiatric facility against her will for up to 72 hours. If the mental health team finds it unsafe for her to be released a court hearing is arranged and recommendations made. If the Judge finds after hearing from the mental health "team", the young lady, family or others who offer testimony, that she is not stable enough to be released from the hold, can remand her to up to 180 days of treatment - even if it is against her will. You might also check to see if she has already experienced this process of a hold and evaluation and find out what "plan" and recommendations she was encouraged to follow. And if you are able to make contact with her social worker or evaluator ask for some guidance and do's and don'ts as to how best to provide support.