Unforgiving Promise to a deed

[Dorretta Harrell]

Hello: any one with advise please respond.

My mother and father did not have good credit 35. years ago. So their only son and his wife took out a home loan for them. My mother and father have paid the loan and the deed will go to the son and his wife. So in reality my mother and father just spent their life buying their son and his wife a home. Two years ago my father died without the deed in his name and my mother is 84 and has requested her son for the deed so that she can make her will. There is really no paper work  to show ( she trusted his word) except for the 35 years of payment from my mother and father's  bank account to their son's account for the mortgage.
What and are their any legal avenues that I can help my mother with. It's unbelievable. My parents have been tricked in believing that this was their house by fixing and maintaining it all of these years. The house is in N.C.
Thanks for your support