My sister's husband and his family is harassing mentally and physically
It's regarding my sister's married life.
This getting bitter day by day. At first, it started with a smalls fight and abuse by my brother in law sisters, and other family members, and on 19 August 2019 Bangalore, they physically abused her and throw her out of the flat, and took her 4 months baby from her, and my brother in law her elder sister his son they all went on a trip. They snatched her phone so she can't contact anyone. But her apartment Secretary and neighbors helped her to contact us. We went there and file a complaint against all of them at Bangalore HLA police station. (His family already facing 2 divorce cases. Her sister did same to other two of his brothers but each time they get thru somehow ) The Head of the station call them for counseling and my brother in law given in writing that he will keep my sister and baby in a separate house and none of his family members ever going to interfere in her life. My sister was sick and so weak due to dengue so on 16th March 2020 I bring her my home with her husband's permission. Since then she is here her baby was severely sick but he didn't even come to see her. He didn't even bother to call my sister. A few days back I asked him why you are not coming home they all miss you and want to go their home now. He didn't say anything.
While his father wrote three letters to us and in all those letters they threaten my sister in different ways. We also give him a reply.
But I really need a suggestion on how-to legally proceed on this.
My sister is depressed about the way they behaved in these 4 years of marriage.
Please guide me