a question for the color-blind

So Dead Rick, one of the protagonists of this book, is a skriker. That means he's a faerie who can take shape as a black dog. I have a scene in which he's talking to a (faerie) character whose eyes are many shades of green.

And it occurs to me that dogs are red/green colorblind.

Advice on how to describe this from his perspective? My experience with colorblind men is that some shades I call green they will also call green; other shades they will mistake for grey, yellow, or brown. So would ...