That's what I had assumed had happened to his face, sun bleaching. I guess I have been really lucky, my horse doesn't bleach out. That little mare that was a bay roan did once, but she was a really dark bay to begin with, so even bleached she was still visibly a bay roan.
No its not sun bleaching at all! The dark moults out and the yellow takes itsolace! Plus i'm in london and if you know anything about the uk its that we don't get enough sun to bleach anything. They yellow last's from marchish to octoberish.
Their isn't really much colour too him, other than grey. He's legs below the knee are black and his face is changable, some summers his shoulders go quite dun but it doesn't happen every year, i've had him 5 years now and every year he goes a slightly different colour.