Depending on how you read this information about OA’s “brother,” and the events of Season 2, we maybe knew OA’s brother all along. He was maybe right in front of our faces. Prairie first learns about OA’s brother in Episode 4 when Old Night offers to give her some important information, and in order to do this, he’s going to kill her for 37 seconds. While Prairie is in this near-death hallucination, we see her crawl through an airplane bathroom and walk down the plane’s aisle towards someone. Their back is too us, but it appears that they’ve got bright blonde short hair, and are wearing some sort of green, flora-print jacket. More than likely, this is Prairie’s brother, however we never see their face. Just as this person is about to turn around, in the waking world Karim kills Old Night, snapping Prairie out of this dream and robbing her from the last few seconds of this message.