There are seven caring siblings. Mother is 86, in very bad shape, in a nursing home, and has a weak personality. She has been coerced to appoint the one domineering controlling sibling as the Medical Power of Attorney 8 years ago. The six other sibs have had no control. Mother has had medical problems ad infinitum. Two or more siblings wish to have a say in whether Mom has future surgeries, and to have a say in Mom's pain management, as the controlling brother Medical Power of Attorney has switched Mom from a narcotic to Tylenol just hours after her most recent surgery, and is planning a future needless cosmetic surgery on Mom's nose (with Tylenol only afterward). Can a person file for a Joint Medical Power of Attorney when a parent is no longer capable of making decisions and her child does not agree with the current sibling Medical Power of Attorney's actions? Must the original Medical Power of Attorney be overthrown completely in court? Thanks.