The Captain started up, pushed back, taxied out, lined up on the runway, then quietly said - You have control.
After I'd fought the beast to top of climb and engaged the autopilot, he said - You won't do that again, will you ?
I didn't
A similar thing happened to an ex-Captain of mine when he'd been a Brittania co-pilot. A night with too many beers and he turned up the worse for wear with a long trip ahead of him....
After the Captain had flown the take-off, he popped the autopilot in and handed control to my ex-Capt chum. Who then had to fly without the benefit of another pilot beside him for the next few hours - with an ever-worsening hangover. After eventually returning to his seat and taking control for the approach and landing, all the Captain said to my chum was "Learn anything today?"......