He doesn't answer my messages, but I asked a leader to help him. Apparently he discovered they were not his relatives. I traced it back to a confusion between 2 Marriott cousins which I have straightened out now.
He orphaned about 10 profiles and I was able to change those surnames from unknown. But there are still about another 10 profiles that need to be changed away from unknown, where I have added the correct surnames in the "current or other" fields, awaiting correction to unknown LNAB.