Both of my parents were terribly self-centered (and were divorced when I was 11). My mother was academically brilliant and totally lacking in common sense. My father was a driven businessman who had a fierce competitive streak and a lot of conservative values. We had a falling out when I was 50, and I told him to disinherit me. He did, and we only spoke once in the past 17 years. With him, it sprin's not a matter of forgiveness; we are both better off out of each other's life and not causing each other any emotional pain.
My mom passed away last spring; she was significantly demented but in total denial about it, and refused to give anybody power of attorney in either health of financial matters, and had completely exhausted her savings. My sister got along with her growing up even less well than I did, currently lives in Paris france, 9 time zones away and had a clinically schizophrenic son of her own. So she was in no position financially or emotionally to offer anything other than "I'm sure glad you're taking care of this" kind of support.
I'm not sure I'm going to be able to forgive my mother ... I feel a little bit guilty that life seems so much easier now that she's gone, but the overwhelming emotion is relief. Time will tell. I'm getting absolutely no guilt-trips from my sister about it.