Seeing Another User's Linked Accounts?

A buddy of mine who used to be in my linkshell a couple months ago sorta vanished suddenly and I haven't seen him for awhile, but I friended him on this. I know that the character he was using wasn't his main, but I friended that one anyways, and I have noticed that it lists his character as coming online in my friends list a bunch, which makes me think he must be using a different character (perhaps on another server?) and linked the accounts before he left. Just wondering if there is a way to see which characters are linked to who so that maybe I could find his main, just interested to catch up with him. :)

I don't think you can, seeming as its friended by their character, and not the account.. Try PMing them, and asking how they are? They will still get it.