As a person who had grand parents with Alzheimer’s, it's starting to sound like this is my better option. I can go through pain, suffering, and what not completely with it or I can slowly go out without knowing or understand anything that is going on. I think I will take the latter.
A good living will and instructions for trusted friends/family/SO to carry out goes a long way for that.
Its easy to take your life, its impossible(for decent people at-least) to take some one else's life.
Friends and family aren't exactly hitmen.
Most people aren't that 'rational' (or willing to go to jail)