Originally Posted by blackcat
My concern is that he probably gets about 5 min. of instruction each day and then he's on his own. They are not doing any "curriculum" it is just random stuff.

This has always been a point of cencern for me - because "random" introduction of topics and working on them for a week or two would result in gaps in knowledge even though he is learning a lot at school time. This is one of the reasons that I prefer grade skipping to "differentiation".
When my DS was in an class where he got differentiation, he got no instruction at all - just worksheets. So, I taught him the concepts ahead of time using Singapore Math and Beast academy and also sent in a work packet from home. Will this approach work in your school setting?