Ms. Caretaker is good at what she does, but her manner and tone and demeaner is that of a bully. I am the only son. She hates me and I don't trust her and feel she's ripping off my parents by overcharging. How come dad doesn't see this and he puts up with it?
If the Caregiver is an independent contractor, thus not working for an Agency, but on her own, the average is around $10-15/hour [depending on your areas going rate] from which she would take out to pay her own estimated quarterly income taxes, and take out to pay for her own health insurance. She wouldn't have paid vacation days, nor paid sick leave, and no time & half for overtime, etc.
The important thing, as mentioned above, do your parents like her? If yes, consider yourself lucky.... many parents refuse outside help, even refuse Hazel [old TV show from decades ago] if she came to the door. Then you would become the full-time caregiver.
But if your parents like her keep your feelings to yourself and be grateful you have a caregiver that your parents like.