Independent middle school for dyslexic kid?

Our 10-year-old son is currently in 5th grade at Aurora. He is dyslexic, and we are looking for a middle school that will provide a larger pool of kids and still offer learning support for him. We will look at Raskob, but it's so small (like 15-20 kids per grade) that we're concerned he won't have the same social and athletic opportunities that he might have at a larger school. Does anyone know of other independent schools that offer a balance of these two components? Thanks!