Help, bank is stealing the house

To make a long story short. My mother In law passed away 7 years ago without a will. The medical bills where very high because she had cancer and was in the hospital on and off before she passed with surgeries and high cost care. Because there was no will, the estate went into propate,and the decision was made to sell the house. This would have covered all the costs owed and given the family the means to move with out stress. Right away there was a cash buyer for the house, but the bank refused to acknowledge my father in law as legal owner of the home and said he could not sell it. This happened multiple times. The year before my mother in law passed away,they had done a refy on the home and stearns was the refy company ,they had falsified papers and removed my father law from the title without his knowledge. Therefore the bank (Chase Morgan)claimed the property was solely owned by my mother law,And my father law did not have the right to sell the home. The bank stated that they had right to the property and ignored probate rulings and started to try to auction the house from underneath my father in law. This forced him to move from the property that was 6 years ago ,and he has been fighting the bank since then. His sister is a lawyer and has been able to keep the bank at bay for a little while but she does not specialize in this type of case.  To our dismay The bank finally auctioned the house illegally 2 weeks ago and we need to hire a law firm the specializes in real estate law and foreclosure defense.  We have a firm that will take the case but they want a $5500 dollar retainer to get started. We need to file a unlawful foreclosure action to stop the bank from stealing this property and losing everything. This has to happen quickly and we don't have the money, and the bank(chase) will get away with being a big bully again ,doing whatever they want, knowing people don't have the resources to fight back.please help!