If he is Muslim, he is one of us. Otherwise an honorable guest. Its plain and simple.
On the other hand, African themselves can by very inward type, meaning they are much more comfortable with each other than with others.
As far as calling him Kale or black, it does not necessary means racism. I am called "keke (meaning blond)" in punjabi due to my blondish hair, or Gore (i.e. white) due to my skin color at times etc, yet Pakistanis are obviously not being racist to me (Being ethnic Pakistani means I am their race after all). That is referring sometimes to skin color is just a "bad norm" in Pakistan
Off course to some foreigners, some Pakistanis definitely can be genuinely racist in Pakistan. Still however, the point is referring to skin color does not necessary akin to being a racist. Someone should point out to him that too.
Other the other hand, despite initial love shown to Indians by some Pakistanis, most people in Pakistan sooner or later will definitely reject Indians. That is a different story altogether however.