For one, there was no back up plan, no person he delegated responsibility to make transfers in his absence. He said as much in his forbes interview; that he delegated customer service responsibilities but it was him and only him that could manage the site or it's bitcoins. No reason to disbelieve it. Maybe early on, he had delegated but after the first employee theft (the first alledged hit), certainly he would have moved to change that , as paranoid as he seemed to be in some regards.
You continue to make the assumption that he had no backup plan, and you offer (perhaps understandably, as you're not inside his head) no supporting evidence aside from statements on his part that any sane person would make, regardless of the truth of those statements. I've known a couple of guys who got in some trouble and had seven figures to lose, and be assured they both had contingency plans despite their pleas to the contrary. You aren't privy to his personal network of relationships; stop pretending you are. You shouldn't assume getting burned by one employee equates to never "hiring" again. I was once burned to the tune of USD $40K by an employee, which was not a small sum of money for me. I didn't stop hiring, but I did get smarter about it.
Second, even if somehow he gets his sentence reduced, it'll certainly be preconditioned on his turning over his remaining proceeds. They won't say "give us your money and you're free" to his "I'm sorry, I would I forgot my key though" and reply "ok, sounds good, you're free"
Aside from a fundamental misunderstanding of how scenarios on this level typically play out (they don't actually care about his money; they care much more about who he can help them grab to further pad their resumes), you make the mistake of assuming he'll be convicted and sentenced to anything more than a decade in prison. Conviction is uncertain, anything more than ten years is unlikely. Most men can do ten years with the knowledge that they have a fortune waiting on the other side, as long as they're smart about how they conduct themselves following release. Again, he wouldn't be the first guy to play it smart in this regard.
No. There's no way he's being released any time in the future if there's even a question that he could access those funds. Maybe he should start praying that bjtcoin finally reaches its overdue demise so that the Feds don't think he has anything of value any longer. One day...
Once again, the people prosecuting him don't give two shits about Bitcoin. Think about that for a while.