And then walk away.
Human nature is such that the majority want to be liked/loved and understood and i am sure she has had her fair amount of pain over the years. Fighting with her will not achieve anything - she will dig in and lets face it she holds all the cards as you want was she has. I have no idea how she will react to this but if you speak to her face and face and just listen - you may be surprised at the result. Forgive her - stop the hatred and walk away - she may just start to look at your side of things and give them to you -
Crikey! Are you a Vicar?