It depends on how he learns. Visually? (pictures, movies, presentations) Verbally or written? (books, essays, speeches) Kinesthetically? (projects, examples, experiments) etc
I think with aspies unschooling is a good option when they're older (once they got most basic skills in the realm of schooling.) Most have a curiosity for learning. I learn way more at home than I ever did while I was at school, and I like learning what I want to learn. Aspies usually have the childlike curiosity about things even when they are older.
I really like nonfiction books about the topics I'm interested in. Videos can be interesting too, but they're hard for me to pay attention to. I think a library card is a good idea if you haven't one already, they typically have DVDs, magazines, etc.
But don't let him fall behind in a realm. For instance, my struggle is with mathematics. And now I have to make up for the basic math I never did pick up on very well in school. But the plus side is I can learn in a way that makes sense to me with other resources.