Even if his parents came from Africa, it doesn't change that he has grown up in Europe and has been shaped by that.
That you even have to guess about his parents having been immigrants shows that your initial conclusion was only based on his skin color. Black skin -> allowed to write about Africa. Which is total nonsense as first there is one does not need the permission to write about it, second there would be no authority to grant such permission, third Africa not being a unified culture anyway and fourth, skin color has nothing to do with culture.
A white person born and raised in, say, South Africa, would know more about the culture there as a black italo-german. Sure he can do research about Africa, but so can any other European, even white ones.
So why should he be allowed to write about "Africa" and a white person isn't?