I think a lot of the case is going to depend on what was discussed (and recorded) in the chat room. If the log had information that could be attributed to your friend's son, that's going to be a potential problem.
He admitted that he participated in the raunchy chat. He knows he should never have driven to the meeting point, but foolishly did. But he's now in prison. The last I heard, they had him in solitary confinement--apparently it's what they do to all new inmates during the first week of their stay in the county jail. It's really a shame. This young man comes from a good and loving family and has a supportive church behind him, so I think he'll be fine. But it's a difficult penalty to pay for a stupid lapse of judgment.