I read the following answers about dealing with an ungodly parent:
They resonate with me as I am having similar issues with my own mother. I realize people are responsible for their own behavior just as I am for mine, and you can't make them change, you can only change yourself.
It's difficult to not let her hurtful words get to me and I often have a hard time trying to ignore her behavior and not let it affect me. Sometimes I remain silent because I don't want to argue, other times I feel the need to defend myself and speak up. When she is angry she resorts to putting me down and making personal remarks against me that have nothing to do with the situation. Things like me being still single at 25 is because no guy wants me because I'm "miserable" and "the train is passing you by". She has told me that I have a problem and that if I did get married, my husband would either leave me or kill me. She's also said, "get help before you kill yourself". It has never bothered me to be single, yet she uses it against me, nor have I ever wanted to take my own life. She has brought up issues from the past that I've long since moved on from to use against me as well. I've been cursed at, told that I need to "get a life" and have a "miserable life", that I need to see a therapist, and on it goes.
The thing is that I've never been happier since starting my new job, I'm enjoying life, and looking forward to the future, so it makes no sense to me that she accuses me of being miserable when she is the one using personal insults and attacks against me, trying to bring me down. She claims that she is happy with her life, yet I don't understand how one can truly be happy if they deride someone else and then accuses the other person of being miserable.
It's very hard not to respond to those things, and I know I am wrong for doing so because I should know better than to let it upset me. Sometimes I don't bridle my tongue when I'm upset and I'm not proud of that. Often I feel the need to defend myself instead of choosing to walk away, even if she continues with hurtful words.
How can I do a better job of not letting these things impact me? How can I improve upon forgetting about the past and living better for the future?
I'm assuming you still live at home, so the answer is to move out. "For this reason a man shall leave his father and his mother, and be joined to his wife; and they shall become one flesh" (Genesis 2:24). It can be true for the woman as well as the man. Leaving puts distance between you and your mother's hate-filled talk. It allows you to control what she can say to you because anytime the conversation turns hateful, you simply say, "Sorry mom, but I have to go now." If she tries to call to berate you, you simply said, "I really don't have time to listen to this nonsense. I'll talk to you next week." Then hang up and block her calls for a week.
What you will find over time is that things gradually calm down. At first, there is rage at being stood up to, but eventually, there is a desire to try and get along. It might take several years before there are more good conversations than bad but stick with it. Just keep reminding yourself that you are in control of your own decisions. If she makes bad choices, such as berating you, then the results were also her choice.
You are still responsible to make sure your mother is cared for in her old age, but you don't have to be the one doing the care directly, nor do you need to remain at your mother's beck and call your entire life.