@Andy_R
If it ever happens again here is my advice.
Suggestions based on bringing home a very merry Lovely Wife from her works 'do' last week (no vomit though so can't help there):
In general; carefully think through what you are going to say in case there is room for misinterpretation. If possible say nothing until you are spoken to and then resort to nods etc. I can't stress this enough.
Here are some examples of how to react to stress inducing situations ; other events can be substituted:
Don't mention the 40 minutes standing around outside the pub in freezing cold fog whilst she was saying goodbye to everyone for the umpteenth time. This could provoke a kicking off response.
Don't treat the I'm plugging the wrong seatbelt into the socket for the fourth time fiasco as a joke - it is obviously really good fun based on the laughing it was accompanied by.
Ignore dodgy advice re driving in fog.
On arriving home ignore the difficulties in getting out of the car (took ages) and very definitely do not offer to give her a helping push out of the car door. Also ignore the obvious confusion as to why it is dark at nightime - it's just not worth trying to explain.
Do feign amusement at the tripping up the steps to the house incident and be helpful rectifying the ensuing shoe falling off debacle.
Once indoors do offer to assist in taking party clothes off as some zips and buttons can be very problematic.
Do sit quietly and listen to the same anecdotes from the event being told over and over and over.
Do make a sandwich on request as apparently this is why Lovely Wife is drunk in the first place. Unfathomable!
Don't be so stupid as to assume that offering a glass of water is the right response to an "I'm thirsty" remark. Oh no, the right response is to drag a bottle of plonk out of the fridge and poor a glass to quell the thirst.
Do make soothing noises regarding sudden appearance of headache.
Do not worry when a visit to the bathroom to remove makeup results in permanent disappearance ie collapsing into bed never to be seen again until the following morning.
And above all - don't mention anything over breakfast the next day apart from what a pleasure it was to pick her up and that you'll be happy to do the same next year.
Hope this helps.