I get blamed for what my Mom does too. Don't sweat it, there is nothing you can do.
I spend an inordinate amount of time trying to work issues between W and kids, W and her sister, W and my parents...Somehow, I always got the blame from both sides.
People here on the board tried to tell me, but I didn't listen...Oh, well.
Hope you have better luck. Heck, I'm not that crazy about my Mom and her little notes to W were still my fault.
