Why this morbid thought? Mom's dying, as we all are, but she's reflecting on it, and not in a good way. She's focusing on how all the negatives in her life, how her kids didn't embrace religion like she did (I'm crazy, not stupid), how she wasn't the best mother she could've been (the whole motherhood book wasn't on sale at the time), etc., etc. Even dad has told her, you live each day, how you want to live it is up to you. You can either be happy and grateful for what you have, or be pissy and negative, the choice is yours.
I hope that when I get to my mother's age, I won't be incapacitated with a major illness, as I know that's a big reason why she doesn't have the bluebird of happiness perched on her shoulder. But I think having the right attitude will also see you through a lot.
And on that note, I will get off my soapbox and make way for someone else.