Rude Questions From Strangers

Lately my mom has been perturbed by acquaintances and strangers asking her a weird question. My mom is 79 and my father is 81. My mom could pass for 50 in a heartbeat. My dad on the other hand is in the advanced stages of Parkinson's. He no longer walks but shuffles with the aide of a rollator. Sometimes he drools, and he has trouble speaking. Yet they manage to go to the local senior center three days a week. Last week a rather rude woman, whom she had only spoken to once or twice before asked if that man she came with every day was her father or her husband? Mom was aghast! When she told me I was horrified at the womans rudeness and audacity. It seems to me and mother agreed, that she should have quietly asked one of my mothers closer friends at the center. More importantly, why did she need to know?