I've seen an article on this family before, in a homeschooling magazine. She homeschools that whole family, it is amazing how they function.
Once you've spent time teaching the older ones, the younger ones start getting it by osmosis! LOL!
I read an article about this family the other day. The older kids help to teach the youngers ones to read and do their math, etc. It also makes for much more harmony between the kids; they learn to be friends with each other because they're not learning the attitudes of many school kids these days that say kids are 'supposed' to hate their parents and siblings.