Black mail,threatening, holding personnel documents.

My wife died recently,as we both were sr citizen aged 67 years. wife purchased house,on her own funds,after so many years house trasfered or registered to her brother son with out taking my signature or opinion. After her death, since we are aged ,she kept all our documents like bank pass book,fd document,jewels worth approximately 1kg in her bothers house for the safety purpose. After her demise immediately next days of cremation demands me to Handover the house key and vacate . For that we requested give 3 months time ,so that we can look for the house for rent.once we find rented house of our payable capacity we will vacate and hand over key. For that they refuse and denied to hand over my my personnel document,threatening, blackmailing over phone and life risk threatening. 1.Now please advise me,can they keep my personnel financial,pension record,jewalles of my wife. Black mailing.permitted as per which law, I eligible to live in the house or immediately vacate and hand over the keys.which law applies? Ok advise