I think you're smart to ask those questions and worry those worries! I wish you didn't have to, but school is what it is.
I guess I'd be less worried about your son missing something important if you were talking about a poet skipping geometry. I suspect geometric proofs and the rigorous logic they require would be very useful for an economist or a doctor. Again, this is a clueless English major talking...so please take with a very large grain of sand.
Could you call a math teacher and ask about the specific courses directly? Especially if there's a teacher who's GT-friendly, you might get a better take on what's REALLY necessary and what's wasted time than you will from our well-meaning but *highly general* generalizations.
Or maybe you've already done that?
