What to do when your student is convinced that he will be the next Einstein?
Let the standard processes of education and research take their course. This student will probably not survive them to receive the degree, and that is as it should be. Tough love: warn, then let the system do its thing.

The central issue I see is that this student is clinging tenaciously to a goal of disruptive fame rather than a goal of advancing research. This happens; it's a difficult thing to screen out at the application stage (where unreasonable ambition is not entirely uncommon, and not usually a dealbreaker). You can suggest that this is an inappropriate goal, and it sounds as though you have -- but you can't force the student to hear, much less change.

I would be inclined to keep my interactions with this student as concrete and immediate-goal-oriented as possible. Have an agenda for every meeting, and pull the student back to it when a megalomanic rant is imminent. Deflect, e.g. "Yes, but when will you have {thing with imminent due date} done?" or "Interesting. Write that up into a conference abstract and submit it to {conference}."

You are well within your rights to "fire" the student as your advisee, I would think. I don't know how that works where you are (or whether it's even possible), but to some extent your students become part of your professional reputation, and this one will not reflect well on you.