Regarding my sisters issue

Sir, my sister got married recently. After her marriage, she is being mentally tortured by my brother in law and his mother and remaining his family members.Mainly her husband is ignoring her and insulting her for everything. He used to talk over the phone for hours and chat with them even in their private time. He used to hide his phone and never says anything to my sister. He behaves strangely and will not behave like a newly married groom. Couple of times, he caught red handedly to my sister as she has a look at the close and private messages he got from some other girls. When she asks about that, he will shout and behaves recklessly and scolds my sister. He used be insults my sister physically and mentally. He used to ask more dowry and asks my sisters to go for work and get money to keep food for her. She was fed up with the attitude of her husband and his family members. One day the same thing happened and when my sister asks about the message, he tried to manipulate by shouting at her and scolding her. But this tym my sister fed up with this and asks my brother to come to home.when my brother went to his house,he behaves as if he didn't do anything and said everything bad on my sister and behaviour and same issue carried for couples of days and my brother tries to convince my brother in law, he said he don't want my sister and asks him to take her away from his house. When my brother tries to convince he didnt listen. So my brother took my sister and came to my home. It's been 2 months from that time. No other communication is there, when we tried to talk they are not ready and they don't want to talk anything about this and saying all wrong on my sister. We our family members are suffering from mental torture with this as it been just 5 months they got married. And also they are blaming whole my family for this and saying everything wrong on my sister. Please kindly help me to solve the issue. How they will come and take my sister back. Please let me know what is the procedure