You may think he trusts you. I hope you are right. But trust is a big problem with CSA survivors. And they are very good at hiding things. Many have had to in order to survive. And don't think that the way he is now is how he will stay.
I didn't think my CSA was that big a deal. I thought I was over it. It was both denial and ignorance. From your introduction post. He has no desire to seek professional counseling and feels that he is "over it."
I say bullshit to being over it. He hasn't even touched it. He is just fooling himself if he believes that. Try to bury it maybe.
Search your local library for books on CSA. Read what you can.
I just picked a spot in F&F further in the past and picked out a couple of threads at semi-random. Read those and then work your way forward/back reading additional threads. There is a lot of information about what others have gone through. While you will get people responding to your posts it will only be a small fraction of those that have come and gone. Once you know more you may be able to ask. http://www.malesurvivor.org/board/ubbthreads.php?ubb=postlist&Board=2&page=68http://www.malesurvivor.org/board/ubbthreads.php?ubb=showflat&Number=340276#Post340276http://www.malesurvivor.org/board/ubbthreads.php?ubb=showflat&Number=336761#Post336761http://www.malesurvivor.org/board/ubbthreads.php?ubb=showflat&Number=263921#Post263921