I'm sure he's not screaming as high as he can. That's a pretty easy range to scream in. I would HOPE he could scream higher than that if he wanted.
Those vocals are closer to "black metal" screams than "death metal" screams.
For example, this is a lot higher (albeit not extreme metal vocals):
[VIDEO]http://www.youtube.com/watch?v=rJp7LT4HTYk]RoadRunner United The Concert DVD Live Part 7 of 25 - YouTube[/VIDEO]
I don't know how to explain that style of vocals in the video you gave, but I find it relatively easy:
(most similar vocals to what you posted are in the chorus)