Need protection by seperation

Hello, My sister was married 17 years back.My brother in law showing his cruelty by beating and by words. He has several bad habits gutka,cigar,jarda pan,drinking alcohol.And he borrowed rupees in lacks from others without inform to my sister.And he have illegal relation with another lady.he kept his name as a husband for her in electoral card(we have proof).my sister have confidence that they got married.we seen some nude videos when he was with her,and he kept camera in bathroom when my sister was bathing.we seen that also.but we don't have proof.he throws my sister every day.on OCT 3 my sister left from him and went to at my mom.she kept a letter in women police station on OCT 7.they gave 15 days duration to settlement day is on 26 per their rule they don't punish that stupid.But in these days also he is doing torture by phones and by direct.Still my sister wants to put case on him immediately and she wants to be separate from him.they have two boy(15) edict to father's enjoyment like hotels,street foods,no restriction to study.One girl(9) has been fear to stay with her father.she is too intelligent in studies,other activities than her how can she put on case and how she separate from him.where she can get real loyalty?Pleasea