Hi,
I think my mother screwed my siblings and me up. She passed away a couple of years ago and I am still grieving partially because it is difficult for me to accept that being in a bad shape myself I could not do better for her to have been or feel better her last months on earth. I do not believe in afterlife so, I cannot think she is in a better place now.
I had forgiven my mom already when she passed away. It took a long time. I think what was helpful to that process was to research about her childhood and other circumstances. I could see how her circumstances had screwed her up, as well. I do not think she had many options, really. She did not have much margin to maneuver. Understanding her development helped me to see her just as a human being, a companion in this journey. I am not sure if this is helpful to you but I wanted to share it just in case.
I am sending you a hug