My opinion? Let the internet teach English. Give him the basics, and then let him learn on his own. English is widely used, and so he'll probably learn it just by being near it.

Same with Thai or Korean. Once the basics have been learned, just being around people who speak it will allow a child to learn it. Don't forget to get him lots of books though. Don't be afraid to give him complicated stuff.

Teach him science, philosophy, math, all sorts of useful skills. That's what I'd do. Kids love learning stuff.