Hi, I'd like to help you with your question.
I agree, from your description it sounds like your mother does have mental health diagnosis, specifically a personality disorder.
A personality disorder is characterized by someone who see the world in a different way than most people. They have traits and characteristics that were developed at a very young age, probably to cope with abuse or trauma inflicted on them as a child. Children need to have their needs met and when they live with abuse or trauma, they cannot get them met in a normal way. So they change their behavior in order to try to get their needs met. It usually does not work, but by then they have adapted to the new way of seeing the world.
Your mother tries to blame others and control other people because she knows no other way. She cannot relate normally to get what she wants. In the meanwhile, you cannot get her to see her behavior is harmful to others because she has no insight into her own behavior. She only sees everything from her own perspective.
People with personality disorders are difficult to treat because they lack the insight to see what they are doing is harmful and therefore, have no desire to change. So getting them to see a therapist or get help in anyway is usually difficult at best.
You and your family can try asking your mother to see her doctor. Or if she goes for regular visits you can call the doctor ahead of time and let them know about what your mother is doing. Sometimes a person will listen to their doctor over their own family members.
Also, learn what you can about personality disorders. The more you know, the more information you will have to relate to your mother and possibly help her. Here are some resources to help you:
Also, consider counseling for yourself and your family. Dealing with a family member with a mental health diagnosis can be very stressful. Your doctor can refer you to a therapist in your area or you can call the United Way for clinics in your area.
I hope this has helped you,