You're being obtuse. Ask your friend their facebook name or send them a friend request + message rather than requiring the service to verify with certainty that

You're being obtuse. Ask your friend their facebook name or send them a friend request + message rather than requiring the service to verify with certainty that they are who they claim to be. How is it supposed to work? Exactly how it has for the majority of users for 10+ years. If your long-lost friends and former co-workers and classmates wanted you to find them then they would make it easier to do so.