I'm going to refuse to speak to my dying mother
Why do you want to do this?
She always treated me poorly growing up.
She's dying, though. I don't know your relationship, but you might want to put things aside as soon you're never going to have the chance to talk again.
I'm doing myself a favor. I don't need to spend time with her.
You should really try to take the time to see her. You may feel that way now but when she's gone, she's gone and there's nothing you can do about it. We should try to spend time with our parents as much as we can before they leave us.