Ol' George is pretty much the only white guy who befriends the family. And how does he do it? It's pretty simple, actually. Listen to Lilly Sue tell it:
"He talk like any other cracker. What make him different he de firs' one I ever seen ain't try to act like sump'n he wasn't. De mos' is so shame of what dey is." (111.80)
Unlike other "crackers" (which the novel uses as a class/cultural marker, rather than a derogatory term), Ol' George has no desire to suck up to rich aristocrats in the hopes of becoming them some day. In fact, this is the novel's interpretation of much of the physical abuse perpetrated against black people by poor white people: it's an expression of jealousy and anger towards the wealthy.
But Ol' George is nothing like that. For instance, even after he gets hired as the family's overseer, he chooses to work alongside them rather than supervise them. They even coach him on how to act tough around the massa so he thinks Ol' George is really tough. It's pretty amazing, actually. Eventually, Ol' George and his wife practically become part of the family, which shows that the Kinte clan agrees with his belief that we should only "'judge anybody by how they act'" (111.72).
In the end, the family repays this kindness by allowing Ol' George and his wife to move to Henning with them, despite some other families being hesitant about it. If nothing else, the practically familial relationship between Ol' George and the Kinte clan gives us some hope of racial reconciliation in the wake of this massive historical calamity.