Can my siblings overturn POA?

I have held POA over my father who has lewey body dementia for the past seven years and it has been absolute hell with my siblings. They will not offer assistance and have accused me of stealing my father’s money. They even went as low as making a false claim of elder neglect which was proven unfounded. I go above and beyond, but they are simply jealous because they are not controlling the finances. I don’t trust them and I live in fear because there’s no telling what they we will do. There is a Cease & Desist letter against one sibling to protect myself, our father, and my daughter. I sought out an elder care attorney to help qualify for state insurance, so I guess that’s a start. She is also aware of the family background. My father should be enjoying these years of his life, but my siblings are Greedy!!! They don’t visit or anything but continue to make up lies.