Not to downplay his talents but he's been playing the way he does for 3 years on piano's that are kept perfectly in tune imitating sounds that sound exactly the way the piano sounds (at least in pitch). This is learning by imitation, the only way we learn, and doing it with only the necessary information, the fastest way to learn. He has never looked at music - which really is completely meaningless and irrelavent in making music - so it does not provide a useless distraction in his imitation and leaning.
Or your post like this:
I've just met this 4-year-old toddler and he can talk! He talks pretty well. I asked has he ever read Stephen King or Dostoyevsky and he said "no, I can't read." My jaw dropped when he said this. He's been talking for 3 years according to his mother, and hasn't read a word in a book yet. This was incredible! I asked how he learned to talk said that he doesn't know, he just does.
On the piano, there are only 12 notes that are repeated. That's just 12 notes that has to be remembered. Once it is remembered, it is very easy find and play it. By notes, I mean the
sound it makes, not the relative location on the keyboard and definitely not those dotted ink spots on pieces of paper. Once a sound is heard, the sound is played on the piano - imitation. It gets a bit more complex when more than one note is played together but it's not difficult if the 12 sounds are already understood.
The reason we are not more like this is because we rarely imitate immediately after hearing a note because the CD player is in our bedrooms, not the room the piano is in. And because our memory is not sufficient to hold a piece of music in its entirety, we never repeat the sounds on the piano after it is heard. Because of the lack of note-playback technology (another person playing another piano or a computer that can play the music, etc.) when we sit at the piano, we do not learn through direct imitation. We, instead, rely on pieces of paper with ink dots all over them and imitate the sound these dots make.

Imagine a parent only making the sounds used by the English language so the baby will learn those sounds. Then he shows the baby a piece of paper with letters on them and shows him how each sound is written out. Then the parent stops talking for good and instead gives him a book to learn how to talk and use those sounds. In 5 years of this, he will have learned how to say "Chopsticks" and "Happy Birthday" but he's really good at reading and saying aloud the words as he sees them.

This is how we classical pianists learn how to play the piano. Many people think and repeat this falsehood: music is a language. This is balognious to the utter most degree. There is no dialgue in such music; no one ever makes a few notes and someone responds with another few notes. If language is the exchange of ideas through the same medium, then music is not a language. There is no exchange, only sounds thrown at another who cannot respond. To visuaize this idea: you are playing Fur Elise while someone listens. When you finish, the person does not play in response to what he has heard as he has no idea how to. There is no exchange; you are just giving money to a street beggar who will never give you anything back.
Because classical pianists learn in the manner we are taught how to play (by reading sheet music) many of us will never learn how to use the piano other than repeating notes on the pages. If this is the most effective technique, why is it that parents do not teach their children by handing them a book? If we learned how to speak by imitating our parents, then why not music?
Coopes, your friend is a perfect example of the most effective way to learn how to make music. Some jazz pianists learn how to play in the same manner, though the difference is that there are other people who can make music for them to imitate. This is why I have said that their should be two pianos so one can play and the other to imitate. It's much more effective than handing a child pieces of paper with dots all over it.
I have bashed just about everyone's piano teacher on this forum and the piano teachers on this forum for teaching the way they do. For this, I will not apologize but will ask to prove me wrong.