Unfortunately, dementia is a very slow but ever steeper downhill run; the brakes have failed; there's a hairpin bend near the bottom; oh, and did I mention the drop, and that there's no guardrail, and by the time you get there you won't remember the journey...
So far, sadly, there is no reversal to this condition...
I can perceive of a number of ends but, imho, seldom are any so bad as this... the slow loss of everything and everyone you've ever known... about as cruel a curve-ball as life can throw you...