Offering a discount is not refusing service to others. If he were to turn away non-Caucasian customers, he'd be in violation of the law, but how is it any different than offering moms a discount on Mother's Day or Dads on Father's Day? Or vets on Veteran's Day?
You know he is going to give everyone the discount regardless, right?
I think he is doing this to tweak someone.
Those are not protected classes.
Race, gender, religion, disability, etc.
If someone is denied that discount based on race, he will be breaking the law.
“Offering a discount is not refusing service to others”
The law doesn’t hinge on refusing service. If you are charging more to customers of one race (or any race except white), that qualifies as discrimination as well.
“how is it any different than offering moms a discount on Mother’s Day or Dads on Father’s Day? Or vets on Veteran’s Day?”
Non-mothers, non-fathers, and non-veterans are not “protected classes”. Races are a protected class.