Yes, usually champagne or some sort of cocktail.
Finger sandwiches, devilled eggs, and since it's my inlaws, there will definitely be  some form of alcoholic drink!  I'll need it!
I adore brunch.  Best options for a meal, in my opinion! That's nice! Brunch is usually served between 11AM to 3PM. Do you have alcohol with yours? Not usually, is that normal?
Brunch is a combination of breakfast and lunch eaten usually during the late morning to early afternoon, generally served from 11am up to 3pm and regularly has some form of alcoholic drink (most usually champagne or a cocktail) served with it.