Remedy for father's legal trouble as sister showing suicidal tendency

We are a small family of three father,son and daughter. my mother had suicidal tendency and schizophrenia, and currently my sister is showing similar signs, unreasonable aggression, abusive language and suicidal tendency, we sometimes had to fight her for her own safety, and every time we had fought with her she screams for no reasons as if we were beating her brutally, she pretend to cry gather attention of the society for proving we are torturing her but instead we were tortured by her. My Father is liberal in nature and dont want to take her to asylum without her will. I would like to mention Society is not aware about her illness. My Question is What if she commits suicide in her room, will it cause my father legal trouble as society is not aware of her tendency, what should you recommend in this case, taking her to asylum, informing police or society?