Thanks for the comment! I remember watching videos about this when he was younger. We actually didn't teach him numbers or the alphabet--he would point to signs on walks and say a letter then we would add another letter or two at the same time. So he just gradually learned them.

But I also am very much in the camp of "it doesn't matter what he knows right now. Kids advance in different ways at different times and it mostly just levels out" All you can do is amazed at how fast they grow and try to help them out as much as you can.