Adult child of an alcoholic parent please advise?

For the past two years my mother has been drinking excessively. It has really taken a toll on our family, my sister has children and doesn't want them anywhere near our mother. My fiance doesn't want to go to my parents house because everytime we do it's a gong show. Sometimes my mom will call me around noon and she'll already be slurring. The worst part of it is that she'll completly deny that she's been drinking and since we don't live with her or near her we can't exactly leave work and go over there to try to stop her. It seems like she really doesn't think she's doing anything wrong. Has anyone else gone through this or does anyone have advice on how to make her realize she's tearing our family apart?