This is a very nice letter. I think she will read it, I know I would out of cruiosity, but what her final feeling on it is, who knows. I hope for her sake, she can start to see why you believe as you do and starts to do her own investigation. One never knows what one thing will get them to really thinking.
I also see that with the latest WT material, they are trying to reach out to those that left and try to get them to come back. I guess, she had an alterier motive in her call to you, glad you stood your ground and that you were polite about it.
Keeping my fingers crossed that your letter will get her to thinking.