Yep, boundaries with my folks helped a lot....OK, with my Mom helped a lot.
My sister is a recovering alcoholic and cocaine addict. I was not around her during the height of her use as she was living in California at the time. But sis would call my mother, and my mother would call me......you get the picture. I finally encouraged Mom to just leave her to her own devices.
My sister has been clean and sober for more than 15 years now, that I know of.
Good luck! There are many of us who understand!!