Just make sure to wet/mist the hair when you brush..don't brush him dry. He is changing colors and will continue to do so for quite some time. As mentioned before, the color changes start at the roots, so that is normal.
If his hair is coming out in clumps that concern you, I would speak to a vet. Just to make sure he's not having some sort of allergy or dermatology issue.
He's cute as a button
