Gunnar Glasses

I have PPKs with cobalt snow frame and an amber lens. They're hard to get used to at first but seem pretty effective for a one-time purchase, and are very lightweight so it doesn't even feel like you have them on. And if he doesn't know already, the only difference between the models is the frame shape, so the only real effect the model type will have is how comfortably they fit on his head.

Bump

If he really needs the filtering they provide he could try this software here that applies lenses on your computer screen image based on the position of the sun. http://justgetflux.com/

Otherwise he should go to a local shop and test the frames so he can see what fits best.