The manager they brought in to bring him in line has been one of the best, kindest, and most human managers I’ve ever met. (But she doesn’t fuck around.)

She’s also an absolute shark at knowing the system, and without going into specifics, has done very well for everyone on my team that has been even modestly competent.

I honestly feel bad for the guy. He was too far in the hole of anger and resentment to realize that he’d been handed a whole new opportunity before he squandered it.
Shortly after I was hired, several other people were hired in to help with the flow of work, and my team went from being sort of an embarrassment to one that, quite frankly, is awesome. (And we still have a good work-life balance.)