How Can You Do It?

There are several homeschooling curricula that require massive (to D anyway!) amounts of reading. I can't imagine D ever being able to read enough to make this in any way viable unfortunately. Reading an outline, then a biography, perhaps a fiction novel of the subject, then watching a movie and discussing the whole subject would cover a lot, it would be hard to forget after all that. But HOW can a kid do that? I love to read, I read a lot, and I read quickly. But D doesn't. We're only lucky that he has enough native intelligence to pick up quickly without quite so much immersion in a subject. (Can I say that - without so much immersion? Doesn't really make sense but I hope you know what I mean.)
The problem with not coming at a subject from several different angles is that he only gets one point of view. The textbook or novel author's, screenwriter's, whichever. I'm thinking of Sonlight, TruthQuest, Greenleaf (something like that, that's not right!). They require a "spine" - a basic text - then much additional reading as well as activities to mix things up a bit. It sounds like a wonderful way to learn but I have to stick with textbooks. So sad.