My sister & her husband home school their kids for religious reasons. They do participate in church activities so they get other kid interaction.
Overall they are very well behaved and smart. My biggest fear is that the father is really set in his religious and anti-govt ways so he is constantly teaching them pro-gun, pro-war, anti-abortion, anti-LGBT, anti-evolution, anti-obamacare, anti-any religion but christianity, you get the drift. The son is 12 and is considering engineering but will really struggle with liberal college life.