Hey, Sadness. I'm very sorry about the situation with your mum. My father was a alcoholic and added lots of sadness, pain and confusion to my life. I resented him greatly until he got sober and we reconciled at the end of his life. I have severe depression and my parents weren't always there for me when I needed them--they were caught up in their own drama. My mom didn't drink but she was very co-dependent and always tried to keep dad from the consequences of his behavior. I believe your family will one day understand, for if your mom continues to drink she will face consequences for her actions--it's a progressive disease and will get worse as she continues down the alcoholic path.
I wish you all the best. There is a friends and family forum here that I think would be very helpful.