On the other hand, he finds numbers delightful, can add two digit numbers and knows his multiplication table up to 10, loves squares and square roots, and can do simple algebra problems in his head (equivalent to solving 3x+1=28). He once sat by himself with his blocks for an hour figuring out all the triangular numbers ("step squad" numbers) that he could make with the 200 blocks he had.
I think you just have to try different things and see what the kid latches on to. Lego, drawing, music, whatever. Reading is not the only way to activate your brain, and I think peer pressure is a big part of why kids want to learn to read once they get to school. That and there are just too many ways to be entertained these days (video, audio, toys, etc.) while reading takes true grit.