LittleBlueTruck:
I'm so sorry about your mom's diagnosis. I can understand how your thoughts and feelings would tend to run wild at this time.
I am going back and forth between logically telling myself I tried very hard to get her to a doctor and short of having her committed, i couldn't have tried harder. But a lot of guilt is creeping in and feeling preemptively defensive thinking that family members will come after me. I cannot wrap my mind around the part where she might die. She has indicated she will not agree to any medical care and wants to die. I don't know what to think or feel.
Why do you think that other family members "will come after your"? Why should you have more responsibility than other family members? You aren't responsible for any of your mom's avoidance of health care. You don't have control over her.
One logic is that refusing to get treatment for mental health issues can be equal to not seeing a doctor for other health issues. I'm thinking that she likely hasn't seen a psychologist or psychiatrist for her mental health issues?
Perhaps you and your brother can discuss the situation and pursue getting a mental evaluation for her. If it's determined that she isn't of sound mind, family may be able to get involved with decisions and become informed of the options. If someone is already named on a medical power of attorney, perhaps it could be used if a medical professional deems that she is not fit to make health decisions at this time.