It sounds as though you need to discuss it with him, to get it out there.

What I would say, is that he's the one who gave you personal info about his old band... without that, you wouldn't have found out the other stuff. Also, you say he's too old to understand how accessible info is on the internet and yet, he's using a pseudonym and has locked down his FB account - which suggests he's reasonably internet savvy.

Sounds as though you are torturing yourself a bit, with this. Hope you are able to talk openly and I hope he's responsive. I'm glad you have your other T.