85 year old mother with dementia in care home against her will. Brother upset about cost?wants paperwork aquired from Drs and clergy .

If your mother did estate planning, she likely did powers of attorney for health care, personal care, and financial management.  The agent(s) she named in those powers of attorney have authority to do the things described in those powers of attorney.  If your mother did not do estate planning, and has no powers of attorney, it may become necessary for a conservator to be appointed.  Even with powers of attorney, your brother would have the right to petition the court to have someone appointed as your mother's conservator (of her person and of her estate).  (You have the same right.)  Conservatorship proceedings are exceedingly costly and time consuming, so you want to try avoiding that if at all possible.  Doctor and clergy conversations are covered by privileges, but if you are not a doctor or a clergy person and your mother willingly gave those things to you, that privilege is likely lost.  A conservator steps into the shoes of the conservatee, and can obtain such confidential information.