The horse is about 10 - 12 years old so he's not too old. But he has a very strange mane with a lot of white hairs. The coat has a lot of white hairs too and they are placed all over his body.
And now I see an white spot on his back and I don't think that it's something made because of an ill fitted saddle.
Here you can see the strange spot
White hairs all over his body
The whole horse