This hits so close to home and you've laid it out so well. I tell people that I was the parent in the home and didn't have a childhood. I was raised with the severe parentification. It was like my mom's joke in our home, "I had kids so they could clean the house" was one of them.
Both of us had to take care of all the household chores, and being the oldest, I had more responsibility, taking care of my younger brother, pets, grocery shopping, etc. when I was very young (like 8 or 9). I never saw her lift a toilet brush or a bottle of Windex when I was young. My brother was the Golden Child, never making waves, and was the emotional support for my mom. I was the scapegoat, blamed for everything that went wrong in her life, being an accidental pregnancy. My mother alienated us from our dad and we never got to develop a relationship with him.
It's the worst kind of abuse, to take your childs life from them when they are growing up. Both my brother and I have suffered severe dysfunctional relationships as adults.