Even if he wanted to refuse her money because of race, he’s a total dope for saying it publicly.
Besides....it’s just plain bad manners. Obviously born in a cellar and never brought up.
After spending years living in Asia; it is an Asian tactic to try and renegotiate a deal at the last minute. Indians and Koreans are the two most likely to do that. My wife perfected the tactic while we lived for five years in India. She still will negotiate in some shops here.