There seems to be a facebook account for him, who's friends with a bunch of LW people (from my end there are 13 shared friends). How about simply sending them a message over facebook and a friend request?
As a general rule if you think that the person wants to stay annonymous by using a nickname, why publically write a post about the link between different accounts?
[Comment removed because like its grandparent it leaked information about a third party's identities.]
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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