Wife not letting me see my 23 months old son

My friend got married in 2015 and they have a son and are living in pune. After few years of marriage wife got suspicious of husband having affair with his office coworker which was baseless. This created friction and they had a physical fight in April 2018 ( both hit each other ). After few days they said sorry to each other and things started moving. Wife kept some pictures of the fight. In few months the mother of the girl came and started living with the couple. Both are working and mother in law used to take care of the child. In few months she started interfering in the personal issues of the daughter and in Nov 2019 during the argument with both wife and mother in law my friend left the house. The next day when he came back his mother in law did not let him in. His family also talked to his mother in law and wife but both are reluctant in reconciling and not letting him see his child. Wife threatning to call police and filing domestic violence case. My friend is really frustrated of this situation where he can't do much with the threats he gets from his wife.