I have been worried for a while that my youngest might be colour blind. When my MIL has him she has tried a couple of times to play games and talk about colours. I asked her today how he had been and she said she didn't think he could distinguish between the colours. She also said not to worry yet. I am probably over reacting (he is 2 3/4) but I remember when I felt my DD had a problem and no one else did. Unfortunately I was right.
MIL said he knows what we mean when we say colours and she did wonder if he was just being a pickle.