Sibling feud over POA, desperately seeking advice.

I need advice on behalf of my mom who I help with taking care of my grandparents. 1 1/2 years ago, my grandpa got sick and has slowed down significantly since. That was when my mom and her three older siblings found out that my grandparents granted my mom POA and executor in 2004. My eldest aunt wasn't happy. The other two older siblings didn't care at the time. My oldest aunt is very narcissistic and controlling and made up a bunch of lies to get my other aunt and uncle to side with her and go against my mom. My uncle rarely visits and checks on my grandparents and my aunts who don't work don't want to help my mom take my grandparents to the doctors, get their groceries or pick up their medicine which is why I have stepped up to help her because she works 2 jobs and has two bone on bone knees. My eldest aunt said she wants to enjoy her husbands retirement and doesn't think their children should be their "slaves". My eldest aunt has threatened several times to strip away my moms POA which my grandparents don't want. She wants them put in a home. They don't have dementia but deal with short term memory loss and normal aging of the brain which my oldest aunt is trying to claim as them being incompetent. They still cook dinner, bathe themselves and remember our names and major events, etc. The doctor hasn't claimed either of them incompetent and don't think they are ready for a home in the near future. My oldest aunt and uncle recently went to my grandparent's lawyer without them knowing to coerce their lawyer into thinking my mom is making my grandpa sell his things and isn't taking care of them and to get them to sign a document granting them access to their medical records even though my grandparents didn't want them having access. They also showed the lawyer an edited picture of my grandpas face all bruised from falling which never happened. Fast forward the following week when the lawyer reached out to my mom, she went there with my grandparents to show my grandpas face and clear up the lies they told him. The lawyer said he didnt want to get in the middle of a family feud and basically made my grandparents sign the document to grant them all access of their medical records to settle things down. My grandpa called the next day upset and told the lawyer he was going to fire him for going against their wishes and the lawyer fired back and said my mom made him call and say that which is 100% false. We revoked the medical record forms with their doctor to the lawyer. This feud has my grandparents and my mom upset. We got some other legal advice about the lawyer incident and are currently seeking a new lawyer but we are afraid of what my aunt is capable of especially having the other two siblings on her side and her erratic behavior. She purposely killed my grandpas car so he couldnt drive, snuck his house key to make keys for my other aunt and uncle, told my mom shes gonna have her nurse daughter bring covid over there and we need to let them starve because people with dementia that her daughter works with dont want to eat and want to die. My other aunt has physically assaulted my mom over this POA, and things just keep getting worse. I could be wrong but I believe they're afraid of not getting anything out of my grandparents when they pass even though they don't have a lot to give. The doctors have all of this written in their records and know what's going on and have it documented that only my mom and I have been taking them to the doctor this entire time. All my mom wants is to keep them healthy and in their home and take their doctors' advice. I hope I'm making sense... We just don't know what to do when they have strength in numbers and have followed my oldest aunt's lead. My mom knows if she gives up her POA it won't be in the best interest of my grandparents and they don't want that either.