Achromatopsia Support Group
Achromatopsia is a medical condition (also called maskun or rod monochromatism) characterized by a low cone cell count or lack of function in cone cells; these are the light receptors responsible for color perception. People with maskun have difficulty seeing in bright daylight.
To help your boyfriend I would say ask what you can help him with usually people with this can only decide what is best. I am 42 and my sister and I both have it.