I know that some people call the Minnie Riperton and Mariah Carey upper head voice a “whistle register” but I had never heard a man sing like that until I saw this:
It’s Adam Lucas, of Australian extraction. 
The only thing I know that approaches it occurs in Gunther Grass’s post-War German classic novel, “The Tin Drum”, (only that’s fiction). The main character learns how to stunt his growth to avoid growing up, and can also scream high enough to shatter glass. He uses this to join the carnival circuit and also entertains in cabarets. The movie version is very bizarre, and not for the faint-of-heart.
wow
Wow… sounds just like someone’s hearing aid giving feedback.
