I can only speak from my own experiences, but it was from my heart. My late mother was mentally abusive and quite cruel. I left home as soon as I was able, and got as far away as I could. Even so, I loved the witch, and was foolish enough to continue to try to EARN her love, long long after I should have given up. I think this is hard wired into a child, and in my case it really did take.
When she got sick (with multiple myeloma) I essentially commuted, every other weekend half way across the country to try to help. She never offered to pay for the air fare, or anything else. She never said thank you. And she continued to abuse me until she finally died.
Her dying is the only thing that put an end to it.
I feel like I did the right thing and made the effort, and it was a heroic one on my part, and undertaken at considerable cost. I was working full time, had a house, a husband, and a 5 year old. I used to get on the plane immediately afterwork on Friday afternoons, and come back on the first flight on Monday morning, going direct from the airport to work. On those weekends, I didn't see my son, my husband, or my home. I got to the point where I didn't even see myself.
And for what? In a futile effort to get her to love me? Trust me: you can never make that work for you. In my case, in doing my daughterly duty, I played right into her abusive hands.
It wasn't worth it, and neither was she. Even now, 20 years later, when I think of what I put myself and my family thru, I kick myself.