He's Very Musical!
I am currently pondering audi0 integration therapy or similar practices.
Leelo has been playing a lot of his favorite tunes on the kazoo, full length and pitch-perfect. However, he cannot sing the same songs; he will sing the first few words rather fuzzily and then start humming the rest. He can follow along when I sing them, and fill in words at any point (again, pitch perfect).
This makes me wonder about a auditory processing disconnect that perhaps something like AIT could address.