Something that may appeal to both an unschooling mama and her sneaky reader son is selecting some non-fiction books about whatever topics interest him. Look for ones with lots of pictures or diagrams. Offer to read them to him, but when you're not reading them together, make them easily accessible in places he might like to look at them without you around/noticing. His room, the car, even the bathroom.
My DS was reading very early, but did not like to read books aloud to us or in front of us. We read a chapter from a novel together at night, and sometimes he would read on ahead after he was supposed to be asleep, so we knew he was reading at a high level. But when we started getting books about space, which was his obsession at age 3-4, and he realized that reading could be a tool for gaining knowledge on his own he really began to be more comfortable with it.
