Mother (91) everything she owns is held in trust for me and my sister. How do we get some of her assets to pay for her support?

She needs someone to stay with her every night. We don't leave her alone for too long during daylight hours. I take her to Adult Day Care while I work. I pay to stock her fridge so family volunteers who visit have food to cook for her and themselves while they are there. I take her to get her hair done weekly and sometimes her toe nails. She likes to go out to eat and to the dollar store. Her monthly income is meager. I don't know what to do or how to do it to get something she owns liquidated for her care costs. It is a nice problem to have that she has some assets, but how do we access it?