Grandmother denying to transfer property to us as promised what to do

I m from a Hindu Brahmin family. My mother (widow) has been living in her matrimonial home since marriage. My grandmother owns the property we are living in as per WILL made by my grandfather. She had been assuring my father that the property will be transferred to his name after her demise. But Due to my father's sudden death in 2006, she changed her mind and asked us to vacate the house immediately. We filed a case in civil court but failed to get justice. Now that we have appealed in the high court and got a stay order, what are the chances of my mother acquiring the property? Please advise.