I don't know if it is specifically racist (even though it's looking that way).
I think it's more he's boorish, at least when it comes to your friend and, really all of his wife's biological children. To treat one differently from the others is nasty, and it can happen in families where everyone is the same skin tone. And for him to double down on this for 4 (!) decades is just nuts. He erected a wall in his head, and he never let anyone in unless they passed muster for him in some manner. And it may be true that the only way that anyone can pass muster with him is to be lighter in skin color. And that's sad.
As for the other things, the restaurant, etc. You are hearing them third hand so it's hard to tell.
No matter what, he does seem to judge people on appearance. Even if he's not technically a racist, he sure as hell is unfairly judgmental.