Shouldn't the caregivers be receiving the funds?

My sister has POA for my uncle and he is receiving Aid & Attendance(?) at $1600.00. However, my uncle lives with my mother (her brother), my father and me. Both my mother and uncle have Alzheimer's, my uncle is bedridden and incontinent. My father and I do the caregiving. My sister agreed to pay me $600 per month prior to the aid & attendance-which I found and she took it out of my hands. As of today she is behind two paydays of $300 each and when April 15th comes up she will be three behind. Shouldn't that check come directly to me and my dad? I don't want to stir things up but I work 24/7 and that $900.00 she owes me would sure help. She's constantly on vacation somewhere (doesn't work) why should I be scraping for gasoline or cigarettes?