How would he live or what would he do in life? More importantly, what should be done with him to make him useful or at least neutral rather than being a negative on the society?

Are you a tool, or an object yourself? Can I throw you away because you’re broken, or because a newer version of yourself has been released, or because I don’t like the way you age?

Probably not, because at least in your own eyes you don’t consider yourself a tool or an object, you’re not something, right?

Why is that? Because you’re a person. You’re a human being.

Well, good for you and, also, nice to meet you my dear fellow human being.

The thing is that with or without skill, we all are human beings too. We’re persons, we’re not tools at the disposal of some ‘owner’ who is free to break it and throw it away when not needed.

Given that, one realize that the fact of being alive is not about being ‘employable’ or ‘useful’. It never was. Believers would say it’s a miracle or a gift, I’m not a believer myself but I kinda understand that idea: it’s… so much more than all we can understand.

Sure, each of us may need to be able to get food and shelter, true that, but then your question instantly stops being about ‘what should we do with unemployable people’ to become the, imho, much more interesting why is that civil society (aka, all of us) is allowing a handful of its own members, the billionaires and corporations, to decide they have the right to destroy the way society works for all of us and to render a lot of us unable to earn their living, just so that handful of billionaires and corporations can make more money? And why is that we should not object to their decision?

Now, since I answered your question, allow me to ask you mine.

Why do you think people should be categorized by their ‘usefulness’? And, if we were to accept your premise (which I obviously don’t want to), would you happen to consider yourself one of those ‘useful’ that would still deserve a place in that new AI and robotic-powered society?