As far as I know she was on good terms with the elder Harts until their passing. Things did sour between Martha and Bret eventually because Bret was all 'muh legacy', which, honestly, I think was mostly bullshit and mostly rationalizing him chasing a payday (his relationship with Vince is really fucking complicated as he was kinda a father figure that he didn't really have with Empty Headed Stu. But also, the whole whinging about his legacy is kinda stupid because everyone knows Bret's contributions and a single DVD smear piece wouldn't have changed that.)
I say that because Bret is still trying to make money -- there's a restaurant that opened up in a casino that is basically a museum of his career. All of his belts are on display, plus some of his gear and other things.