Do you not hate the TSA and how difficult traveling in the US can be?
Given how hard it is to travel with innocuous items, no one should be surprised that he had difficulty carrying $58k in cash.
It's not surprising that it was taken from him. That's exactly what corrupt, bullshit officials do the world over. That's what most of the world expect; that powerful people take what you have. There was a time when the US asserted it was better than that. When the US asserted that a man was free to be about his lawful business. Those times are gone.
The TSA will absolutely stop you if you try to back out of the screening process once you've already started.
Furthermore, nothing in the TSA rules says "no cash exceeding X dollars". If they don't want you to bring it, they should explicitly disallow it.
He got let through eventually. I seem to remember someone escorting him out to let him put in in his parked car, which to my mind seems unusually accommodating but I'm pretty sure that's what happened.