I have been living with&taking care of my elderly parent for 12 yrs and have one older sibling living down the street that only bothers with the parent three times a year. When my parent got sick the sibling took him to the hospital and told the nurses I was not to be given any information and she was in charge and they obeyed. what do I do to protect myself from this happening again.
https://www.agingcare.com/questions/what-to-do-with-a-narcissistic-older-sibling-who-is-estranged-from-younger-sibling-and-elderly-paren-492710.htm
If you do not have general POA and are responsible for housing and care without a care contract you are really in an awful position for these 12 years.
If your parent is competent then it is time for the two of you to see an elder law attorney.
If your parent is incompetent it is time to do that alone and seek guardianship through the court.
I hope also that if you are managing your parents money that you are keeping meticulous records.
Good luck.