His face screams grey. His base color is buckskin, and he has the grey gene modifier, making him a buckskin that is going grey.
Every grey horse "greys" at a different rate. Some are completely white by the time they are two, some never turn completely white no matter what their age. The gene acts different on every horse. There is no way to predict how exactly a horse will grey out (i.e. Turn fleabitten, turn steel, colored or be grey dappled).