Are there any home school groups in your area? Getting involved in a local home school group is a great way to get materials and resources that you don't personally have. Many groups offer courses in subjects like Chemistry for all of the families in the area in addition to group activities like choir or sports. Even smaller towns are likely to have some sort of home school group if you look for it.
Also, are you sure he doesn't read as well as his peers, or does he just not read as well as you remember kids his age reading? From my experience, if he is not reading as well as his public educated peers, there is something very wrong. My boys are home-schooled, and while they started a little "slow" for the first year due to the different approach, they rapidly moved beyond the level of most public school kids and are now pretty advanced for their age. Reading in public schools (or the lack thereof) is a joke with close to half of the students graduating not being able to read. This skill is far more important than any other because it is through reading that you can learn virtually anything else. Make sure that is a priority.