well that stinks.
but, that's exactly the kind of event I'd just excuse myself from going to. Not so much out of any worry but because it really wouldn't be fun or meaningful to me.
if it were my friend, I'd offer to host an alternative celebration of some sort, politely and honestly let her know why I didn't feel I could be a part of it and wish her all the best.
to me - nobody's day is worth my spending a day at an alchohol-centric event with alcohol-centric people watching them do alcohol-centric stuff. MY life journey isn't about that and my friendship and connection to others in my life isn't honored by that.
There's a wedding, a reception, presumably a shower, opportunities to throw her a nice dinner party..... loads of alternative ways for you to honor her and be a part of her celebration.
Just my perspective and how I'd go about something like this.
Best of luck to ya.
