Sometimes, the reason for being an impediment is that this individual is proud of their knowledge and probably derives pleasure from being the sole keeper of truth. Try giving this person the "respect" he craves. Treat him like a guru. Tell him you see him as your mentor. In that capacity, perhaps you can ask things like "I want to learn everything about this message and only you can help me. Can you please steer me right so I don't run into traps?"
I know this sounds a little "help me Obi-wan Kenobie, you're my only hope." There may indeed be no hope. But invoking the ego sometimes works. Likewise, keep asking questions. Ask so damned many questions that he can't get anything done but answer your questions. He'll either complain about you, or he'll start giving you more information just to shut you up.
