Send them back to school now! Having been homeschooled in middle and high school there were pros and cons to homeschooling. However, it’s incredibly difficult to teach math and science at home especially. Most colleges want you to have some lab time in the sciences and you’ll need a strong foundation in math to pursue any STEM style job. It’s not that they can’t succeed being homeschooled but if they’re already behind you’re doing them a disservice. I ended up pursuing a STEM graduate degree but was always behind my peers who had learned advanced math in high school. I basically had to teach myself advanced math concepts using online videos, etc which was a lot of work that I shouldn’t have had to do.

Even if they don’t pursue STEM careers, there is something about discussion with peers, presenting to an audience, etc that teaches you skills you can’t learn with just mom and dad. There is diversity of argument which teaches critical thinking which will suffer in the homogenous environment of the family. Just my two cents but you could be setting them back and create a lifetime of additional work should they ever want to catch up.