My Mom is 90 years old and has Dementia. She lives in an Alzheimer's unit that is a part of an assisted living facility. She is WELL taken care of. But she is VERY moody. She is happy to see me when I visit. After I am there for 6 to 7 minutes, she is ready for me to leave. Is it best that I stay? Or should I leave? Her sweet caregivers tell me she looks for me. Advice, please.