Sister volunteers to care for mom on weekends. Should my pay be separate from hers?

If my sister volunteers to take her on the weekend should my pay be separate from hers?This is a big issue in November. I only got paid 183.00 and the rest of the 500 I get a month went to my sister. As co guardians it was never discussed they just came up and blindsided me with a check for 183.00. He thinks I'm frauding my mom when I don't even get her money he does. And pays me 500 out of 1600 she gets for the month. I'm not sure what the going rate is for full time caregiver for my mom.