I really have no idea what the federal/airline 'guidelines' are for such.
It is possible the pilot was just being an asshole.
It is also possible that he was risking his career if he did not turn the plane around. I can't imagine that he wanted the hassle of probable paperwork, delays and such.
It is probable that the reality is somewhere in the middle.

I think that it is a sad sign of our times that common sense/intelligent action are buried under regulations to keep the lawyers/politicos at bay. It's time to dig out the Harlan Ellison and re-read 'Repent Harlequin, Said the Ticktock Man'. It's becoming more appropriate every day.

Hugh