Books are not enough. Smart kids are lonely. Get him into a good school (or other community) where he won't be the smartest one. That happened to me at 11 when I was accepted into Russia's best math school and for the first time in my life I met other people worth talking to, people who actually thought before saying words. Suddenly, to regain my usual position of the smart kid, I had to actually work hard. It was very very important. I still go to school reunions every year, even though I finished it 12 years ago.