And under what cause could you possibly get him sent to prison? He's still processing payments and hasn't ran away with anyone's money, at least for now. He's also closing GLBSE, which is not a crime in itself. People don't go in prison for merely pissing people off.
I think a lawyer might find a lot of good reasons, even if you could argue that "processing payments" may reasonably take a thousand years.
At this regard there is this thread:
Legal Actions against Nefariohttps://bitcointalk.org/index.php?topic=117655.0