When she complains, she wants your sympathy. The specifics may not matter, she just wants to hear that you care about her. Some people stay negative because being positive is too much of a burden. She is unloading that fear that no one will care for her if everything is good. When the cognitive ability is waning, more subconscious will surface.
So, validate her by agreeing with her, and don't tell her she is mistaken about something. If something is missing, tell her you will have it replaced.
May or may not work, but worth a try.
（告诉她你总是在想着她。）
