Your mother is lucky indeed to have such a caring son. Instead of just rejecting her, you wrote to us to try to find some answers. At some point, she’ll recover and appreciate your loving efforts.
I can’t make a diagnosis on the basis of a short letter. But I can make a few suggestions:
First, and most worrisome, is your sister. She is dangerously underweight and may be suffering from anorexia. You mother may feel so helpless and scared that it is driving her crazy. I hope your family is seeking treatment for your sister. She needs it. Your family needs help to understand how best to help her.
Secondly, your mom moved from a place where she probably had supportive friends and an active life. She may be unable to cope with the change. You didn’t tell me why you all moved or if she took part in the decision. If she didn’t want to move and now feels isolated and angry, she may be depressed. Some people show depression by being irritable and angry as well as sad. Then again, over-cleaning, using make-up and over-reacting may be signs of the hypomanic stage of bipolar disorder.
And, she may be peri-menopausal which can be very challenging for some women.
Those are only guesses. You need to get her to some qualified doctors to see which, if any, is correct. I hope your father is willing to help you persuade her that she isn’t herself these days. Emphasize your love and caring and ask her to do you all the favor of taking care of herself by getting evaluated and accepting some help.
Do get her to see her physician. She needs a complete medical work up to make sure that her hormones are in balance and that there isn’t anything else, like a vitamin deficiency, that could be amiss. At the same time, I would encourage her to see a counselor for two reasons: First to learn some ways to help her daughter and, secondly, to talk about how to start a new life in a new home. Finally, I would get her evaluated by a qualified mental health provider to make sure that she isn’t developing a mental illness.
I wish you all well,