I find difficult parents, especially mothers (for their daughters) can maintain their difficulty 'reach' even when they've passed on. It takes considerable work (on our part) to let go of not only the grief for the mother you never had, the one we all feel we deserve, but also - the anger.
As an orphaned/neglected/abused daughter even I can say: one gets to a point where it is what it is/was - and there's simply nothing else to feel.
As far as being a 'non failure parent' mother that I hope I am? I don't even think about it. It's not a competition with my late mother for one thing - I am sure to make and have made mistakes and I try my best. I don't scrutinize myself or judge myself in the parenting Olympics. I can stand it if my offspring don't like me (although they seem to) or take distance because in life, anything is possible, no matter what your intentions. I just hope I am kind (while unpatient), fair (while biased) and decent (because that's all I can be as an awake human being).