Whoa, I never said he was abused by any family member! Where did THAT come from? My first hunch would be that the priest (maybe even a previous priest) had established an inappropriate relationship with him over time.
But the fact that you were there for him does not preclude that something bad did not happen. Like I said, he may have been able to talk about the priest because he felt enough control.
It's plain this is an emotional issue for you (as it should be!), and I shouldn't be poking around in it. I don't say that you're emotional to say that that in any way nullifies your objectivity, just to say that its not a good subject for me to be debating with you, since it is a rightfully upsetting subject. So, I'm going to shut up now.