Many, many (if not most) students and/or parents make decisions based on finances, and many parents on this board have told their children they will only pay for the college giving the best financial package.
So … you are thinking about how it would turn out for you if you told him that Stanford and Yale were off the table. You would not be asking these questions if you truly were allowing him to make the final decision. You need to tell him.
Old thread, but I wouldn’t put Stanford or Yale a “notch above” UChicago. Ask anyone who graduate from HYPS whether they considered UChicago a peer academic school, and I think we would all say we were intimidated by those graduates, and felt UChicago was more academic! With all due respect to your talented son, he’s just a teenager and doesn’t know which institute will “open more doors” for him; that’s a rationalization but it’s untrue.
Having said that, the feel of the campus matters. (I personally prefer the UChicago campus to the other two, put that’s personal choice). You have the luxury of choice. He has preferences, whether ultimately valid or not, that should be acknowledged and considered.
The decision to give him the $80k after college is an interesting one, and should internalize those externalities to have him own that part of it!
While $80k may not affect your lifestyle here, understand that that is just a bonus consideration.