I am so sorry, and this sounds harsh, but — barring a fleeting miracle — no, she won't be competent to recognize it. You will, and that is a terrible burden. None of our death-with-dignity or aid-in-dying protocols really account for dementia. But you know, as awful as it is to face, that her life is becoming unlivable. The doctor has to stay within his professional (and legally safe) bounds. I hope you're spared it, but it's very possible you will have to make a hard decision under duress. Please know that you are NOT guilty, whatever you do. Sending an unasked-for hug.