Domestic violence

My friend's daughter got married 4 years back, now she has 3 years twins boys. She has been mentally tortured by her sister in law, mother in law & their relatives. His son in law has verbally abused his daughter and came to beat her so she came to her mother's home with kids two months back & her husband is not talking to her & the kids & also not given money for the kids also. Then the boy's father called their parents & spoken the matter falsely & warned them to send her back within 15 days or else they will proceed further. The girl's husband knew every tortures done to the girl by his family members but not supporting her so the girl is afraid to live with them due to such domestic violence & they don't want the girl's parents or relatives to visit her. The girl is very much hurt as the parents gave dowry what they demanded along with full wedding expenses, not even a penny they shared for wedding, during wedding they behaved like good people & said they will not interfere in their life but her sister in law is dominating her by totally occupying the home with her husband & children after that girls marriage. Now what can be done to solve this? The girl want to live with her husband & children peacefully but his parents & relatives are greedy for his salary & keeping the boy under their control as to not talk over the phone also to the girl. Can anyone suggest what can be done to solve this situation?