An application is a portfolio of components. There’s no such thing as “making up for” something.
Yes, very strong ECs and AP Stats would be more attractive than weak ECs and AP Stats. But the same strong ECs and AP Calc would be stronger. Strengths in one area don’t make another area meaningless.
This doesn’t mean Calc is the right answer, just understand the reality of the tradeoffs. An A in Stats is probably better than a C in Calc. An A in Stats vs. a B in Calc could be an endless debate.
How would I bring that up to him? Like, how would I ask?
Both are relevant.
If you choose AP statistics and later go to a college where the business major requires calculus and calculus-based statistics, then you may regret not having chosen AP calculus in high school.
Explain you are trying to weigh your math options next year and that your goal is to apply to top colleges. Ask if calculus is needed to be considered the most rigorous schedule. Note you are deciding between AP statistics or calculus but would prefer stats.
“I just don’t see why taking AP Stats instead of AP Calc would significantly decrease my chances of getting into a good school.”
It would depend on your definition of good school, but places like UT-Austin and UW for OOS will expect Calc, definitely over Stats. I posted in another thread, adcoms have said that Calc is the first math course they look for, and the biggest mistake applicants make wrt math rigor is taking Stats over Calc. The reason is that these colleges want kids that take advantage of the courses they have, even if they’re tough, that’s one of the reasons rigor is so important.