Shadow, I am really sorry to hear this. My mother and my step-dad constantly argue and fight and she's threatened to leave him many times, but never does. Unfortunately, there are very strong women who stil feel like they can't live without a man in their life. there are also people whose pride doesn't let them seek help even when they really need it (My aunt is very similar). I really hope everything goes well with you and your mother. You are both in my thoughts.
By the way, has your mother been formaly diagnosed with Bipolar Disorder? Is she taking medication to help relieve the symptoms? Lithium treatment has proven very successful for those suffering from it.