Learning piano

Learning to play the piano can be frustrating, even more when you're not quite four. W is teaching himself - with mom there to answer questions as needed. I've labeled just over an octive with the names of the notes and when he wants to play a song, I pick it out and write the names of the notes on a piece of paper for him. He'll sit there and play the songs - he even has some memorized. Sometimes he gets frustrated because the letters on the piano don't follow the same rules as the letters for reading. He'll tell me I've written the song down wrong because the sounds in the song title are not reflected in the notes I write ("where's the s?! It has a /s/ in it!"). This morning he sat down to play a song from Nightmare before Christmas, but he was playing it down an octive, so not all of the notes were labeled. When he needed a "G" he played the right "G" (down an octive) but then came to me all upset: "this one is G (the unlabeled), not that one! (the labeled one)" I tried to explain to him that they were both G's and that there were several G's on the piano. It didn't go over well. He finally just went back to the piano, convinced that mom didn't have a clue what she was talking about.