My wife and I moved in with my Dad to take care of him, it was rent free and the bills paid, we ended up moving out because of unfulfilled promises of respite help and without the financial help that was promised. (groceries) My sibling moved in, who also has POA and has somehow managed to draw from a stock my Dad has for all the siblings, and pay themselves $1,500 a month for caring for him and to pay anyone they have come in to sit with him. Is this legal?
If she is doing the right thing and you want to help preserve money spent for his care at this time offer to help with the needs that are costing money.
It may be possible she has a plan for the future and in the long run this may benefit everyone in the family. I would ask her this without accusing her of any
ill-intentions. Seems you know the stress and cost involved, so if she is doing her best with what she has to work with appreciate this a simple Thank You goes along way.
I don't know whether your sister was exploiting you deliberately or whether she wised up fast when you moved out. Whatever the case, don't let this effect your relationship with your father.
jeannegibbs is correct .... keep your Dad in a close relationship, even if you want to scream at your sibs, do it away from your fathers knowing this is going on, his stress level is an important factor as it is for all of your family.
My Boss always says... more hands make less work, the job gets done easier as a team!