Property and Daughter in Law

My name is vinod. My elder son committed suicide recently. There has been a lot of disturbances from my daughter in law family from the moment my son got married since 11 years. My daughter in law was having indifferent behavior. whenever she visits her house then every time they threaten us to file a false case against my son for torturing and not having freedom and even for dowry. then whenever we said for divorce then they always got settled the case by purposefully asking for forgiveness. This has happened 3-4 times. My daughter in law understands this whenevr we sit and make her understand. Then everythig becomes normal. We never questioned nor demanded for anything wheather its dowry or anything else. she understands this and settles down everytime. Then just before 5 years she left communication with her family on the context that they always creates problem in her married life. so there was no communication between our family, son , daughter in law and her family. my son and my daughter in law were living with us. Now after 5 years they again started the communication on a lighter node and then when she gone to her house they again started those things like threatining my son and all again. at that time my son got very tense and he committed suicide leaving a suicide note for not to let her enter this house. there is also one sms indicating that he is afraid of false allegations from her family again and again and is under constant threat from her family. so he will commit suicide. we had lost him. Now she is in her family house. Now i want to ask that they are demanding her certficates to get my son job(as he was in CPWD). we have given them the certificates and assured them for any help. But i am afraid that they can demand house also. So please advice me what to do next. House is on my Wife's Name and i don't have any ancestoral property. We also agrred to give them all their belongins. So please guide me the implication which can arise in this matter. Can we demand a written statement that there is no connection from now onwards withthem for anyhting after handing over the belongings.Please provide me reply