Is there such a thing as a completely useless human being?

This question has two parts.

(1) Do you believe a human being can have no useful function? That is, to be so stupid, broken, disabled, disagreeable, or otherwise damaged, that they serve only to consume resources without giving anything of value back?

(2) Assuming the answer to the previous part is ‘yes’, then what do you think the ethical and/or logical course of action is with regard to that person? For example, if the person hirself is functional to the extent that sie recognizes hir own otherwise complete absence of function, what is that person ethically or logically obliged to do, if anything? What are we, as a society, obliged to do about a person who only seems to exist to consume scarce resources?

Goethe wrote, “What is my life if I am no longer useful to others.” Do you agree? Do human beings have an intrinsic worth apart from their willingness or ability to contribute to the weal of others? What if a person has no usefulness even to themselves? Does that change the answer?

(Please note that I am posting this in General. It’s fine to have an opinion, but I expect you to be able to support your answer with a line of reasoning.)