"Mom, I'm really sorry for what you went through during your childhood. Now will you apologize to me for what you did to me during mine?"
Whose is worse? Who should be the one whose sorry?
This is the tough part, for me at least. I know I can't ask my dad (89-year-old alcoholic raging tyrannical control freak) to apologize -- he has no recovery and certainly feels that he has nothing to apologize for. I don't have as much knowledge of his childhood as you have of your mom's -- so that's tough to gauge.
I don't think there is "a one who should be sorry." I certainly think my dad should be sorry -- but that ain't happening. Asking for an apology would be just as effective as asking him to stop drinking. (I might add that from time to time, he does "try to cut down," but it never lasts. That's how it usually works with alcoholics -- there's nothing we can do about it.)
What I'm getting at is that we are powerless over alcohol, people, places, and things. I'd like to be able to come to terms with my dad while he's still living -- but that seems impossible, unless he has an epiphany and goes into recovery (which seems unlikely, although stranger things have happened). Short of that, I just know I'm going to have to keep working on it while he's still here and after he's gone. I don't see his eventual passing as some kind of point of no return, though, where I have to make amends while he's still here or I'm going to be messed up for life. I'm working on it now, I'll keep at it while my dad's still living, and I'll still be doing it after he's gone. If he's not receptive, he's not receptive -- that's not going to stop me from recovering.
We may "make amends to such people wherever possible," but we're really doing it for ourselves, so we can let go, heal and move on. And -- just to use a cliche -- expectations are premeditated resentments -- so I have no expectation that my dad is going to apologize for anything... even though I think he should!
T