That’s a good idea. But even with the UK safeties, since UIUC is a real option (particularly if he ends up preferring CS over math), I still don’t want him to step too far away from the American system. (Then again, CS at UIUC is pretty much a reach for everyone.)
I suppose he could try to straddle both, doing a schedule like this (each line a year-long class):
10th:
English (req.)
AP Calc BC
online/college math class
AP CS A
AP Physics 1
Spanish 3
11th:
English (req.)
American History (req.)
Calc 3/Linear Algebra
online/college math class
AP Physics C
community college CS (beyond AP CS A)
12th:
English (req.)
Government/Econ (req.)
online/college math class
another online/college math class
Biology (req.)
community college CS (beyond AP CS A)
That’s doubling up on math every year, taking computer science every year (quite a bit past the AP level), and at least getting to AP Physics C. So closer to what a British-patterned education looks like, while still getting to level 3 in a foreign language and 3 years of social studies. I know the consensus in CC is that level 4 in a foreign language and 4 years of SS is best…but since we can’t afford the top 20 USA schools, I believe three years of each is sufficient?