I just want to be close to my mom again?

My mom and I used to have a pretty good relationship until I went through a bumpy road a few years back. She seemed to have gone from a carefree, laugh-loving woman into a angry woman lost in a bottle of liquor who ate little and obsessed about her weight. With help and encouragement from our family, my father, and I, she's doing better. But once in a while my dad will have to leave town to help my brother, and during his absence she tends to break her new "one drink a night" rule. I want to tell my dad, but I don't wan her thinking that she can't talk to me about her problems because I'll go running to Dad when she messes up. I always want to talk to her about it, but I know she'll never see past her opinion (we're both very stubborn) and it'll just end up as another fight. I want to be able to confide in her, and I want her to be able to do the same with me. She would never agreento family counseling, as my dad and I have tried this before. Any tips on how I can start? And how can I make her feel good about herself so she doesn't have to be working out and dieting 24/7? Thanks