False case and mental torture

My sister was married last year. Right from day one her mother in law has been very indifferent to her.She is not allowed to visit my mother place, who is a widow. Her mother in law continuously taunts her and she even has to take care of her sister in laws children. Her father in law wakes her up from the middle of the night while sleeping and scolds her for visiting even though her own husband has sent her. Her husband does not stand up for her. He even called up my mother and insulted her because the promised dowry was delayed. Even though her husband earns a 7 digit salary, he comes up with silly excuses saying that he is over burdened when asked for petty sum. For the first 8 months my mother supported my sister. The problem now is,my brother in law got transferred to bangalore leaving my sister at my mothers place and now does not come to pick her up even for Dassera and Diwali. When we confronted this behaviour they lodged a false complaint against me stating that I am not sending my sister to her in laws at local PS, to counter the acquisition my sister filed a complaint against her husband, father in law and mother in law in women police station for dowry and mental harassment.Her father in law used his influence and did not show up.The pity is that, I have learnt that , it was my wife who has instigated. The case is now resolved and my sister would be moving to bangalore. What are the legal options she has got to get a proper judgement, which out any external influences.