It's not just a stretch, it's completely impossible that he'd actually know anything about the secrets of the tower. I agree with you that he's a super valuable asset we can and should put to work on this, and that he'll have more insights than most, but this wouldn't be the same as say if we recruited a conjurer that once worked in the Shadow Tower.
Hmmm... Genius Loci & Lich sacrifice, then Dracolich? Since we basically have to bring him with us anyway when we go see Bloodraven, we may as well get him involved in preparing for the big sacrifice.
He had problems worshipping Tiamat because she was a "beast". I wonder what he'll think of our trees.