I don't think it's a fake. It's a well trained voice using his natural abilities with falsetto (not everyone can do it - I wish I could). Of course, the reverb is boosted pretty thickly on the swoops and on the high register parts of the song.

He's a counter-tenor. For further interest, here's a link.
http://www.countertenor.demon.co.uk/ct/cttechnique.html