Hello, I'd like to help you with your question.
It sounds like your mother in law has a personality disorder.
People who react as your mother in law does tend to be difficult to be around because they affect how you feel about things. Asking your mother in law to contribute by cleaning up after herself is not unreasonable. However, her response is to make it an issue about you instead of accepting your request as reasonable and following through. This indicates a serious personality issue. And when you are in close quarters with someone who treats you badly, you can begin to feel stressed, upset and anxious about being around them. Here is a link to help you understand more about someone with a personality disorder:
Being around someone with a personality disorder feels draining and unsettling. Their issues can be the result of mental illness or past abuse, where they learned to cope with the loss of love and care by adapting their behavior to get attention and hurt others. They rarely if ever have insight and are unlikely to ever change.
There are different types of personality disorders. Some people feel they know everything and everyone else does not, some criticize and predict doom and gloom with every situation and others are dramatic, making a big deal out of everything. They can also focus a lot on themselves, making you feel insignificant and bothersome. Some are emotionally draining, needing your help with everything.
One of the best ways to deal with someone like your mother in law is to try to eliminate them from your life. However, that is not possible right now with your mother in law. The best alternative is to start making plans to get her out of your home. Living with her any longer is only going to keep harming you. And if you and your family is being harmed by her behavior as much as you describe, the situation has gotten out of hand and become abusive. This can lead to emotional disorders for you and your family including depression, anxiety
and high levels of stress
. Although it is admirable you want to care for your mother in law, her behavior is going to cause long term harm to your family so having her move out is the best option.
You mentioned that your husband is not willing to back you up. It could be that years of being emotionally abused by his mother has left him fearful to even consider crossing her. You have two options to help the situation- suggest that the family get counseling to talk about the situation and find solutions, or go ahead with plans on getting your mother in law out of the home without your husband's support. This may not be the best idea for your marriage, but getting her out of the home is the first priority. You can work on the consequences after she has left.
In the meanwhile, try reducing your contact as much as possible. Avoid contact unless you must be in the same room. When she talks with you, offer short, neutral responses. If she tries to rope you into an emotional situation, have a neutral response ready like, "Sorry you feel that way" no matter what she says to you. Repeat as needed until she loses interest and leaves.
I hope this has helped you,