Would you unfriend someone if they said something like this about your sibling?

My little sister is SO self conscious about her “stache”. She always covers her mouth when I take a picture of her because she’s so embarrassed, but she didn’t in this pic. He slid up on my story and said this. It just rubbed me the wrong way, & doesn’t help that I’m very protective of my family. Would you unfriend this person or would you take it as a joke?