#1
Hi, I've been listening to quite a few recordings by John Lee Hooker and I'm wondering if he's tuned into something that is not standard tuning.

http://www.youtube.com/watch?v=rOyj4ciJk34

^In that video, what tuning is he in? If you listen to him play a bit of rhythm, you can see how he strums all the strings freely and with a beat and it sounds right.

Maybe I'm just confused and he's actually is IN standard tuning.

I tried playing it like he does but it does feel like he is in a different tuning.

Correct me if I am wrong, please!
#2
Sounds/looks to me like he's in E standard. I think that what you're hearing is a combination of things. Firstly, JLH had a great sense of rhythm, so he could go off and do those kind of weird things and still remain consistent. Also, that guitar sounds like it's out of tune slightly.
Only play what you hear. If you don't hear anything, don't play anything.

—Chick Corea