Did you notice that he has a Spanish name and here he says that he composed this polka named after his home town in Texas.

Sullivan City Polka https://www.youtube.com/watch?v=UWiRbmDuXjs

Also, watching his fingering on the buttons I can see that he is self-taught. And, if you listen closely, his roots are in Mexican music evidenced in the polka.

I say all the above because I think he did a great job on Autumn Leaves all things considering. Not to mention that's a great sound he gets out of that box.

Mark