My wife and mil both have vitiligo and they're white as the driven snow. Paco May, Michael Jackson, and my cousin Reggie are the only black folks I know with vitiligo.
And bad news for your friend y-l-a but vitiligo is for life, he will have some times when it will come in and some times when.it won't. It can be dormant for years then he'll start getting spots again for no rhyme or reason.