Your story is very interesting and resonant with my experience.
I don't know the details of your friend's experience, but it sounds like his challenge is family in general. Like him, I have been a good son. There are reasons to do this that have to do with wanting a family and believing in it. Part of that belief is that healing is possible.
What strikes me most about your reflections on what happened is that you see yourself as someone who is not afraid of intimacy. While I understand, respect and admire that, you would need to slowly acknowledge that for someone who has had many boundaries crossed in their family, what might appear normal for an intimate relationship, can easily become problematic. One of the best ways to approach someone like that is with vulnerability. If your friend is anything like me, he is probably waiting for someone who shares their fears up front.
This is because intimacy for us can be confusing at first. If the person who was supposed to be taking care of us crossed boundaries, then any evidence of boldness on the intimacy department is very frightening and is a reminder that it is time to run.
While this might sound like a closed door to a relationship, I urge you to consider that most intimate relationships must deal with the issue of fear at some point.
Hope this helps.