A couple weeks ago, a friend sent me a screenshot, via Whatsapp, of a dating app profile for a girl named "Bilar." The following day, Facebook showed me a friend suggestion for a girl named Bilar. I've never met anyone by that name. I could be wrong but my immediate conclusion is that Facebook recognizes text in Whatsapp-sent images and feeds it into the social network's friend suggestion engine.
Could your friend have friended Bilar on FB, causing you to have a mutual friend with her?
The girl who was suggested was not the same one with whom he had matched. It was a girl in Latin America.