Well, it's normal for that style of slide... He's playing a squareneck dobro - the neck's basically a one-by-two, and you can't even get your hand around it. Having the action way high means you don't have to worry about fret buzz. Bottleneck slide on a round-necked guitar is a different matter, although most slide players do prefer a fairly high action, they still keep it low enough that you can fret it if you want. Dobro is strictly slide only - the action is typically 3/4" or more, so you can't possibly fret it, even if you could get your hand round the neck. The strength of the square neck means that you can tune them in ways that make regular guitarists eyes water.
I only meant to post one vid but got a bit carried away... The sick thing is I had to restrain myself and try and limit myself to 'technically proficient' players as that seems to be the theme of the thread so far. Of those I posted Rory is my favourite by far. So expressive. Tho Sean Costello ALWAYS blows me away when I watch that video.