You can't change what she says, only time will do that. What you can do is change the effect it has on you. This is really hard, but what I did with my mother is ignore her when she started on that topic. I would turn away, change the subject and not engage at all with what she was saying.
You are not her therapist. You will only make things worse for yourself if you listen enough to argue, correct, or interact. If necessary, even say, I don't want to talk about that with you.
Dennis