I need help taking my sister off as caregiver to my mother, but I don’t know how.

My mother, of course it’s an older lady, and she stays in her home in which my sister lives. You could say my sister is her caregiver but I don’t believe she’s doing the job right . For one of many reasons my brother and I have come to the conclusion that my mother is being overly medicated and my sister makes her feel as if my mother owes her a lot and can’t be telling us the things she does like take money from her accounts and to pay off her personal bills like car notes. I work two jobs and I could hardly see my mother but the time I’ve gone ever since my my father passed away a few months ago I’ve gotten closer with her to the point where I am more than sure that my sister is over the medicating her. What she really wants is to keep my mother's home and the small business my mother owns. I already spoke to a social worker but that’s been over a week ago she said she would stop by but to now she hasn’t and haven’t heard from her. This makes me think she’s not gonna be much help. I need to get this taken care of and quick. We’re not rich we actually can’t really afford a good elderly’s home for her but I do want something to be done in order for things to change and my mother could at least have for last year’s of life feeling the love she deserves. please help