Where did you get the info that he is half Native American? His website says:

WHAT IS YOUR NATIONALITY BACKGROUND?
This is one of the most asked questions I get. Both of my parents are caucasian. But so many people ask where I get my "tan"? Well I do get a little color from my mothers side of the family coming from the French side. Other than that the rest comes from being out in the sun.

It's the first FAQ here.

There was some discontent about his being cast as Jacob because he doesn't come from a Native American background.