I am POA since 2011 for my 93 year old now,dying mother. My estranged brother got her to sign POA jointly. He pressured her, lawyer says as she wants us all 'to know about her affairs" and "He is the eldest son." She wants peace and harmony! He has been non-resident for 50 years and seldom visits. (except now! Property is valuable.) Our relationship is acrimonious and he threatened elder abuse ("no food, no clothes, no support") to her lawyer. I spend weekends in her own home with her and she has full time nursing care. He threatens "I'm way ahead of you!" What are the risks, damage he can do? Sell house without my consent??