I think a freind on xbox Live is Racist...?

Towards black people. Well we've been freinds always playing GTA 4, and I've noticed everytime he runs over somebody black in GTA 4(Black Pedestrian in GTA 4) he cheers and SAYS YES!! I ran over a black guy...one day when he found out that I was black...he doesent invite me to anymore of his games or says hi anymore or anything so what are your thoughts do you think he is racist?