How do you deal with a parent (not the one being cared for) who is abusive, controlling and disrespectful?

I take care of my 89 yr old father who has Parkinson’s, dementia and intractable hiccups 220 days of the year during which he spits up his food.
I have four siblings of whom only one helps but is more of a hinderance. The women in my family have zero respect for men including our father. My parents have a large house with property. I take care of all maintenance and have even remodeled the house, not paid a penny for it, saved them $20,000 on one project alone. For the most part it’s been great because my dad and I have developed a really strong bond and I am the only one he trusts completely and only one he confides in. The problem comes from my mom and sister. They never listen to dad or me. For everything I do (when other siblings come to help I still can’t leave) they give me no voice in the house and constantly disrespect me. All three of us had same point of view regarding pandemic safety. When my sister went to a wedding I told her she was not coming back over until she showed pictures of everyone complying with safety guidelines. She absolutely ignored me and my mom backs her. This is a constant problem. Advice? If it wasn’t for their disrespect I could handle everything my dad threw at us. Now without even talking to me they put him in a home. But mom talked to all the other siblings that don’t help about it and asked their opinion. Advice?