Thanks for the input. The idea of a flipped classroom has been mentioned, where DS would learn at home and then do the associated work at school so that he could ask questions at school of his teacher while the rest of the class was working on their regular math stuff. It sounds like EPGY would be a better option for that than Khan, although not free. That was exactly what I needed to know.
Now, to figure out if that would be better than driving him to the middle school every day to learn in an actual classroom. I think I'll wait until the spring to figure this out!
