Can you explain in more detail what "topics he wishes to learn at home". I might be able to give better suggestions if I knew what he is craving to learn.

At 3 I mostly helped my son by providing lots of books, and non-fiction videos when relevant. (My son's passion at that age was animals.) Taking him to museums, zoo's and other such places out in the world. Giving my son open ended toys like boxes of legos (without the directions) for him to create. And mostly not assuming that material was too hard for him, although I did keep an eye out for adult content.