Comment by Freak_NL

It doesn't seem pleasant for the person themself either. Constant frustration, gaps in your memory growing ever larger, disorientation, loss — periodically augmented by brief flickers of recollection of what you used to be — and yet no one can legally end your misery, because you can likely no longer unequivocally consent to euthanasia or assisted suicide, even if you explicitly signed a declaration that you did not want to end up like this — legally, the current husk of your former self must consent, and it can't.