There was no right or wrong answer to the captain/dress question. It's more about recognising equality on the flight deck etc.
I'd be inclined to ask whose round it was, just in case Captain Nigel's name really is Mandy, on a stopover.
As to the vodka bottle:
Are crew supposed to carry alcohol around open or unopened? If he reeks of vodka, ask if he's feeling well enough to operate the flight. If he says he his then you go sick?