What about anything you said equates to bad terms? He was the OC at Alabama, I'd be shocked to learn a single human on the planet thought he'd stay there until Saban retired to be his successor.
And he's been an NFL HC and the HC of multiple P5 college football teams. Not a single soul thought he was in Boca long-term.
Just because you leave a job doesn't mean it ended badly. He wasn't fired, he wasn't embroiled in scandal, he didn't burn bridges, he didn't leave the place in ruins, he didn't flee in the middle of the night, he didn't lie. How did they end badly?