Mocked with Yellowface impression

This really never ends… My brother just relayed this story onto me. It happened to him today, at work.

“After I introduced myself, a 70-80 year old Navy vet family member of a patient, did their best yellowface impression as the patient and another family member struggled to pronounce my last name. Don’t remember exactly what they said, but it was complete with buck-teeth and squinty eyes. I kind of ignored it and went on with my business, but have yet to really shake the “what the fuck was that” feeling. It’s stupid, but it’s bugging me more than it should.”