My DH is color blind...blue/green/red/green/yellow/orange/purple...he struggles with them all. When we went our first date, he told me if he asked what color a blinking light was to just tell him, not to ask why. He will pull over for a blinking light on a vehicle behind him and then find out it was a tow truck. For the past 33 years I have automatically told him what color blinking lights are on vehicles or traffic lights. He didn't want red rose bushes in our yard because he can't tell the flowers from the leaves, but can see the contrast of yellow roses. When we see a beautiful sunset, he asks me what colors it is. He's not any help picking out colors for anything, but on the other hand I usually get what I like best!
We do think our 3-yr-old grandson may be colorblind, will probably have him tested in a year or so.