My 90 year old mother refuses to talk, or do things she is capable of doing. Any suggestions?

She does this with all her children while she is living with them. However, if a child other than her current caregiver phones or visits, she will have good conversations with them. But she can go an entire day without speaking to her caregiver child, and won't even answer questions that she obviously hears. She will never tell you what she would like to eat, but will push away a meal with a look of disgust without even trying it. She also expects her caregiver to do things she is capable of doing, such as wiping herself after urinating and dressing and undressing her. She wants help every time she stands up, yet she gets out of bed to use the toilet and returns to bed without help during the night. Her doctor says she is not depressed, and does not have dementia/Alzheimer's. She broke her hip 3 years ago, and has not lived alone since. She uses a walker. While in a rehab facility, she wanted one of her children with her 24x7. Her health is remarkably good; she is only being treated for high blood pressure and Type 2 diabetes. If it gets to the point that we can no longer care for her and must put her in a nursing home, she would see that as the ultimate betrayal. When we try to discuss any of this, she just shuts down. Sometimes I think she doesn't talk to her caregiver because she is humiliated that she needs this help. But that doesn't make sense when she wants us to wipe her bottom and do everything for her in the shower, both of which she can do for herself. She refuses to use any of the aids she was given by occupational therapists to help her dress and shower. She hates when we bring in any outside help, for even a few hours. The only time she seems happy is when there is a young child in the house. She is a retired teacher, but never had any hobbies. If I understood why she won't respond to me, it might make it easier. If you can try to explain her behavior or have suggestions on what I can try to do, I will be so grateful! Thank you for your help and support.