I'm going to try and stay polite, but as someone who's has had family members die from dementia, you are an idiot.
Your mind failing you slowly over time so that you are aware for periods it is happening slowly with each one becoming more and more infrequent, going in to see a relative who was one of the wisest strongest people you knew now wetting themselves and crying because they are frightened because they don't know where they are or who they are or how they got there.
There is no hubris in wanting to go out of life on your own terms with your mind intact.
Your mind failing you slowly over time so that you are aware for periods it is happening slowly with each one becoming more and more infrequent, going in to see a relative who was one of the wisest strongest people you knew now wetting themselves and crying because they are frightened because they don't know where they are or who they are or how they got there.
There is no hubris in wanting to go out of life on your own terms with your mind intact.