Welcome and thanks for your question I am Dr. German I would be here to help you and give you assistance until you are satisfied, dealing with any family member who has a personality disorder is extremely difficult .
But you have to face the situation how it is and learn to say no to your family . First , You have to be honest and sincere about your mother's medical condition,tell her clearly that if she comes back with you ,she needs therapy and if she does not receive that therapy to model her behavior , she can not live with you .
Do not hesitate , if you do it ,it is gonna be worse at the end . Get ready and prepare yourself mentally to deal with the confrontation and the volatile reaction they could have, what you need here is changing the way you behave with your family ,it could be hurtful , but at the end of this process , they will need to change specially your mom.
Most people with these conditions use the guilty feeling like a weapon ,so everytime ,she uses that resource . Bring it to her attention,like you know mom I refuse to talk to you if you continue making me feel guilty until we can establish a normal mature conversation.
There are also some helpful tips I could give you :
1- If you can not deal with your mom for a long period of time , You have to establish that,so every sister take care of your mom for the same period of time and alternate 1-3 months at most .
2-Maintain some emotional and personal distance from your mom even if you live together so she does not affect your life even more.
3-If she gets angry ,mad or yells at you stop the conversation ,walk away until she calms down .
4-Remember you need to stay your ground and slowly she will adjust to this new relationship with you. I also think that Family Therapy would be extremely helpful for all of you .
5- Establish clear parameters what you can do for her and what you would not do for her.
Good luck if you need any additional help I will be to help you.
If you need any additional information I will be happy to continue further and assist you until you are completely satisfied . Good luck to you and have a good day !
Please leave a positive feedback ( click on excellent or good service ) if you are satisfied with my answer.