There are two (unrelated) issues here:
Firstly, perhaps the young man is torn between yeshivish with black socks and chassidish with white socks. As a compromise he wears gray. On the one hand he is not sure of his derech on the other hand, he should be commended in making shalom between two opposite streams of chareidi-ism.
Secondly, you need to find out if you are color blind. Perhaps the boy is wearing green or red socks. When you are color blind, the colors look gray.
On a different note, you should speak to the young man to determine if he wears grey or gray socks.