My paternal aunt's father in law has a self earned property(house) in delhi region in which my uncle(her husband) had a big financial contribution. 14 years back she lost her husband in an accident. even after husband's death her father in law took loads of money from my aunt in name of that property. now her father in law is dead leaving the property in name of his elder son and that too without any info. she was also threatened by them that they will get the property in their name if she dont give certain amount of money. right now she dont know on whose name the property is actually. keeping in mind that her husband and she contributed a lot in that property should she file a case against them or not?