Hausband married me with cheating though he has wife and baby

My sister had an arrange marriage 6 years back to a software engineer in home district in Odisha. During the time of marriage, the boy to whom she married, was doing job in Singapur. After one week of my marriage, she faced some abnormal and abusive behaviour from her in laws side as well as from her hausband. After two weeks, he left for Singapur and refused to take her with him in the pretext of passport and visa, safety etc. The abusive behaviour increased gradually and her hausband ignored repeatedly, rather threatened her otherwise with slangs of the worst possible manner. Slowly, after one month of the marriage, she came to know that her hausband has relation with a girl in Bhubaneswar and they have a baby too. She talked about this to him and her in laws, but was threatened to keep quite or else would face dire consequences. She brought this matter to her parents. Gradually she was made isolated and all the means of contact (mobile etc.) were snatched away. In that situation, she was forced to return to her parents after three months of her marriage. The matter was raised in family level as well as in their village committe. Sometime police were called to resolve the matter. But nothing was materialised despite of several attempts spanning over subsquent three years. Finally she decided to take divorce and applied in district family court in 2015. Since then the matter is pending in the court. Many times he is escaping the hearing through his lawer (seems influential one) by siting some or other reason. Now she feels extremely cheated and her life has been devasted. He is not giving her divorce. My parents are aged and pretty simple in nature, because of which we are being exploited. I need your help and guidance how to proceed in this matter as it seems all the roads are blocked for us.