Nobody needs to be told when they are drinking/eating or doing anything to excess. You can lie or put a front on to everyone but not yourself at the end of the day.
Her drinking has probably escalated but maybe crept up on her as her excesses are vast in every genre, apparent in her appearance now.
I believe she hasn't heard the word "no" very often and if ever, took exception to it.
I also believe her parents are letting her down badly by enabling her demise. Weird family. Reap what they sow and all that.