A family fight, what should we do?

I am French (though born in Genappe in Brabant), from a very important family. I am married and have have one daughter. I have a brother, too. His name is Charles, and he is 9 years younger than me. Our father died when Charles was very young. And he left a huge estate to Charles. My husband and I were the legal guardians. It was a very difficult task, because competitors and relatives, everybody tried to take it away, legally, by force, and so on. What we endured, safeguarding it, can't be described (La Guerre folle cost me many sleepless nights and worries). But, we kept it safe and thriving for Charles. When he grew up, he assumed control, and he married a very haughty heiress from Brittany. The problem is this: when Charles married, we wanted his new wife, Anne, to consolidate both of their estates and have one management. Anne wanted to keep her estate separate, and we did not see why. Why pay and maintain double management, when one only would suffice? But Anne wanted to be "independent". At the end, we kept it simple under one management. Charles' wife hates us for this. She is very influential and makes our life a living hell. And Charles sides with her, too. And this is after all we did for him! We really can't fight her, she is much more powerful, and we want to lead peaceful life. What should we do?