Is a person with memory issues entirely dependant for survival upon the use of another person’s body without their consent? If yes, then that person gets to decide to withdraw all care at any time.
Yes. Someone with intense mental issues cannot live without the body of another human serving them. That doesn’t mean you are allowed to intentionally murder them. There are ways for babies to survive outside the womb.
No, a person with memory issues is not dependent on any single person’s body for survival. They are dependent upon any person who offers to put in the work, and that person can quit the job at any time without penalty. Someone else will replace them quite easily.
We don’t put slaves in charge of the care for the mentally handicapped. A woman who wants to be a mother does so voluntarily. But if you force a woman to keep a baby when she doesn’t want to, you are forcing her to labor. You are making her a slave. And lethal force to escape slavery is always self defense.
That’s why the example you gave is bad and irrelevant