A white friend of mine was going on and on about how the land isn't ours and it's supposed to be Native American land. How should I respond?
Native American people fought with each other over land and killed each other.
Spain took over Mexico in the same way so this is not specific to Whites.
My friend can give up their land any time they want and move back to Europe anytime they want.
White Europeans developed a modern society that ended violence which every person participated in.
Anything else?
He should give all of his money and possessions to a Native American as reparations and offer to work for a tribe for free for the remainder of his life.
He could be a dealer at one of their Casinos.