I think my mother is likely bipolar, and I don't know how to deal with it?

Bipolar parent? The first thing, is get her accurately diagnosed. People "think" friend or family is "bipolar" for lots of reasons. Most fp's can now diagnose this or refer you to a specialist for it. If a loved one has a signficant mind disorder, think about getting help for yourself and others who love and deal with the one consider going to a nami meeting. Google this, a family and help organization for u.