At the risk of getting serious for a moment--
I would tell them that they have nothing to be ashamed of in being Indian or white, and that The race that's attached to them has no meaning compared to what they do and are as individuals.
That's what the real civil rights was all about. Not the dishonest neomarxist drivel that remains.
It has always been my impression that Indians were chosen as mascots because of their bravery--not out of disrespect. By constantly railing on this subject they perpetuate racial differences which we should have been over a-long-time-ago.