Could someone give me suggestions about family issue?

I do a lot for my children, or at least I try to do what I can. I take care of one of my daughters a lot. She is always treating more like a dog than her mother. She is always talking down to me like I don't even know what I am talking about. She is rude to me and fusses at me for doing something she doesn't want me to do (which is just about everything). I don't want to hurt her feelings because she does have a lot of health issues, but I have feelings too! This hurts my feelings, but I don't know how to address this with her without hurting her feelings. I don't want to cause any hard feelings, but I am the only person that will do anything for her. Her husband has a job and her children are too young. All of my other children live out of state. Besides I am the one that is willing to spend my money to take care of her. It costs me at least one tank of gas and one or two nights of hotel/motel stays. Please do not reply with smart remarks. This is a serious matter and I would appreciate any real suggestions that you may have. Thanks