The exact origin of this clip is not documented, but its appeal comes from the mix of a French sneeze noise and the familiar word frère, which French speaking users instantly recognise as casual slang. Short vocal reactions like this spread through soundboards, messaging apps and short form video because they are easy to reuse without any context. It stays popular because the phrase works on its own, turning a normal sneeze, allergy joke or awkward pause into a quick shared joke between friends online every time.