widow mothers motgage dilema

my dad took my mom off of the mortgage. sge was on the original mortgage and when he refinanced the loan she had to sign the refinance of the loan. this signature page says she agrees to the terms of the loan and gives the loan number. my father was the only one listed as a borrower on the contract but lists bother her and my father as borrowers. my father passed away and my mother couldnt afford the house. under mass law she gets his estate with no will. i looked at her credit statement and it shows her first mortgage as paid and closed in 2003 when the house was refinanced. so she was taken off of the loan. the mortgage statements show her on it on the first mortgage and only my father on the new mortgage. she stayed for a few months after my father died and realized she couldnt afford to pay. she called the motgage company and asked to get an affordable payment and they told her she would have to assume the loan as is in order for them to give her any information. she walked away. since she has gotten threats of legal action from a lawyer and in his letter to her he says he has a paper on the 2003 that she signed. this was to allow my father to refinance as she was on the first mortgage and on the deed. does she have any legal responsability to pay the mortgage because she signed the second mortgage? her name was not on the stipulations of the contract so does her stgning the mortgage make her liable to pay because on the signature line it sais borrower? none of the documents in the contract have her name on it only the signature page.