"Hope they will be ready for college."
SERIOUSLY?! That's not just insulting, that's rude. This is America. Only way to fail out of a year of college is to get depressed over a woman while taking the most advanced courses they got. On the other hand, I know half a dozen Communications Majors and not a single one of them failed a single course... granted they were taking their senior year classes I aced in tenth grade of high school.
For your FIL to suggest your kids won't be ready for college if you guys are putting a serious effort into it boils down to two things, EITHER:
-- He is saying you won't teach them to pass the SOL/LPT tests or whatever they're doing nowdays (we used to call the SOL's Shit out of Luck Tests since the entire school where I did system admin work for a few months before leaving, used to spend a day a week teaching kids to pass the test, which meant it didn't test anything but regurgitation, thinking wasn't even optional.)
-- OR, and this is the nastier possibility he's a conformist asshole who can't stomach the fact that his daughter might accomplish what he himself was too chickenshit to even fathom.
If your kids are sharp and aren't learning "fuzzy arithmetic," or "voluntary arithmetic" you're on the right path. (You know the math classes we've all heard of (though I haven't personally been in one) where we're told the teacher says "2+2 equals whatever you want it to" in order to keep the kids' self esteem high, which means we'll end up sharing society with morons who can't even do basic things like make change... oh wait... we already do...)
I will make a well founded assumption that your kids and the kids raised by most folk on this board won't be part of that idiotry... But they will be the proud members of a lifelong minority. And lonely as hell. Then again, better alone with a pet dog than membership in The Marching Morons.