My son thinks I white washed him

Those weren't his words but idk how else to explain it. My son is 15 and biracial. His dad passed away when he was 2. He hasn't really spent much time with his side of the family. He did this summer and just came home yesterday. His hair had grown a lot. I always have him get a hair cut when his hair gets too long. I told him it's time for a hair cut and he said I never used to cut his hair when he wss younger and what changed. I told him his hair texture changed and it got too unmanageable. He said "You mean black". I said of course not and he can have long hair if he wants. He then said " Well I've been asking for Kong hair since I was 8 but you always said no. So now that its no longer your responsibility to care for it you're saying yes. You never taught me what yo do with my hair. You just shave it off". I'm asking where this is coming from and he says I've taught him nothing about black culture and I sent him to a school where he is one of 3 colored kids. He has no black people in his life to look up too because he almost never sees his dads side of the family. He is tired of being the black kid in his friends group or whenever I take him to a bbq who I the only black kid. I wasn't trying to erase black culture from him. I just know nothing about him. I simply raised him how I was raised. Can I have some advice?