My mom's anxiety upsets me. I don't know what I should do?

My mom has always struggled with anxiety. She seems to have episodes of anxiety when something in her life changes. For example, when we move to a new house she gets so worked up with anxiety that it makes her sick. It has been hard for the rest of my family because she doesn't really help herself, she does go to a doctor but believes that talk or behavioral treatment doesn't help. I feel that there is no doctor on earth that will help her because it is part of her personality and they way she was taught to think. To me, its like trying to change your personality after so many years, it becomes difficult. My problem now is that we are moving to a new state in summer and she is starting to fill her mind with fears. She stopped going to a doctor many years ago because she was better. She is afraid of getting sick again, she is afraid of leaving my sister behind in california ( where we live) while we move to florida ( my sister is 30 years old with a fiance has a nice career etc). My mom doesn't want to do any talk therapy because she says it won't help. I am tired of having to deal with her worries and her trying to control my life with her unwarranted fears. I am so sick of it, even as I type this tears come to my eyes. I get frustrated with her attitude which is like " I can worry all I want and its okay for me to worry, and its just the way it is and I don't have to help myself". I think what upsets me is her degree of selfishness that upsets me and I don't know how to deal with it anymore? I am almost 34 years old and I don't what to tell her or do? any bright ideas?