I see you have edited the message. You added:
Quote:
And the cause of all this domestic drama, you might ask? I failed to pay attention to something she was telling me...
That probably isn't for the first time
What I see is a mom in denial. I don't read anything that would make me think that your mom is bad as someone with NPD. I would say that she's frustrated. All her life she's trying to 'repair' the things that don't go well. Then you tell her it's a disorder and nothing can be done about it. How old are you? All the time of your age has been useless effort. That's what you tell her. You have to give her some time to get used to it and to find good sides in it.
Therefor I think you should ask her to help you to deal with you problems. That way you make her part of the solution and give her a better feeling about it. It's more constructive.