It might be helpful (it is to me) to journal all your thoughts, then reread and write more.. write questions or make an email draft to edit and edit again..
Talk and talk and talk and talk..its the best thing. Talk without judgement. He is going thru this and it took alot for him to open up and talk to you, so at least continue to talk with an open mind. Even if you decide that its not an interest to you it will help him be comfortable talking about all his thoughts and feelings with you..