You will be luck to have a pale skin because most of colors of sunglasses can match you. You can choose black sunglasses for cool look. You can also choose some bright colored sunglasses such as green, yellow for a cute look. You can also choose some distinct color such as red sunglasses. It will make you attracting in many occasion. So, you can choose any colors for sunglasses that you like. Just try one and test it out yourself.
I think the dark or brown sunglasses will suit pale skin tone. To be honest, face shape is more important than skin tone when it comes to choosing sunglasses. So, you should pay attention to the face shape of your friend in order to find the suitable sunglasses fro him? Generally speaking, the shape of sunglasses should be contrast with the face shape of the wearer.