He’s black. Mulatto. May have Indian or Middle Eastern.
Much of the world looks like this.
What is your source for this claim?
Here’s a picture of him as a young schoolboy.
I don’t know of any reason to care what Brand’s ethnicity is, but if you do happen to care, I don’t know of any reason to infer that it’s anything but common-or-garden brunet Celtic-type white southern British.
He favors the long-hair-and-beard style that admittedly reads more “Middle Eastern-ish” than typical white British, but that doesn’t change his ethnicity.