Mentally torture and harassment by Husband and In Laws

I am writing this on the behalf of my sister. She has been married in 2015 & shifted in Delhi where her husband & their parents have already their own home. we feel they have not good behavior towards my sister " agar hamne apne ldki ki shaadi khi or krwai hoti to hmara ghar bhar dete vo", & After one year she fall in their washroom & caught by brain tumour after its one year, We reached delhi to watch her ,She gave birth a baby boy in delhi & we got her in laws are not taking care of her at all which will be threaten her to death due to brain tumour. So we brought her home & start taking care of her. where her two operations are done in next three months thank fully God they are successful & she recover. her in Laws didn't help us a little Even they only come one or two time to watch her, & took her baby to delhi by saying that they will come again to hospital next week. But they didn't come. After that when she releived from hospital they immediately reach our primises to took her to delhi again. We denied for that and asking for child as she need her child but they said if want to send her in delhi sent her we didn't give you child. you take care of your girl , child is our. Then we took help or Police & gram panchayat to bring baby back. & make a agreement of 6 months that she will remain in HP for next 6 months. In between 6 months her in laws harrasing her in phone calls, & didn't come anytime to look her. After 6 months they asked for to take my sister delhi again. We again make an agreement form panchayat that they will took care of her & not harrasing her mentally as already she is a patient. Then they took her to delhi , Afer reaching delhi they started torturing her mentally again, & her in laws make plan to shift her somewhere else which is not a good area at all to live a patient & a child . So my sister denied that she will not go anywhere as she can't live alone. But her in laws make a plan in which they took her all equipment & her child to new house & her husband took her new room by false statement , this happen after 2 days when she reached delhi after 6 months. When sister reach new premises she stunned to see her child & equipment without her consent. So she refused to live there as not a good place to live a patient. but her in laws said now you have live here forever. you do whatever want. Then I called them please don;t do that with her but they stared abusing everyone & mine sister. So we all reached there in delhi & very difficult to find that place as they are like hiding her from every one. But finally we got her & bring her home again. Her husband refused us but we bring her forcefully with difficulies. So Kindly can you help us now what we have to do as we want they have done a lot mental harrasment & tortured us from last 1 year. & we want they must be punished for the same. So what we can do now with this matter.. can you suggest please.