I think sauerkraut has a great suggestion. If not Harry Potter, then another high interest novel. Our local library subscribes to an auxiliary site that has read aloud books. You might check with them. My daughter was an early reader, and most of her teachers attributed it to the fact that she was read to very often as a youngster. Does your son have an IEP? His school may step up and provide more services if they know that you are supportive.