I'm reading this thread and am torn between the amusement it's obviously supposed to convey and very real distress.
People get old and go a bit loopy, it's a fact of life and one day your kids will doubtless be saying the same things about you and I know that you appreciate that you'll miss her when she's gone and all that, but do yourself a favour and try to bear with her because you'll remember all of the times you didn't when she is.
My mother was nothing short of an abusive bitch, however she is the only one I've got and for whatever her reasons were, she clearly did the best job she knew how to do, albeit that was sadly lacking.
I'd personally relish having memories of my mum bringing me out of date sardines and a mankey plastic clock, i'm sure she means well and if it's her way of trying to apologise for things in the past then accept it as such, however inappropriate, some people never even bother trying:)