How can one proceed in dividing assets with a mentally ill partner who's not willing to participate?

My parents are going through a divorce and I'm representing my mother who's not proficient in English. My father suffers from a very severe form of bipolar disorder has gone through 3 different attorneys and now represents himself. It has been so costly to keep paying attorney fees and court costs on my end trying to keep up with his episodes. Our attorney advised us to try and settle assets with him and have it notarized to cut cost and salvage assets. Attempts to resolve this matter has proved unsuccessful as makes unrational demands and continues to stall the process. We have a failing business at stake but I cannot afford to pump more of my own money into it without knowing the outcome of the divorce. How can I help them expedite this process and divide the assets with only one capable and willing participant? I'll do everything I can to make sure my parents are taken off but Because of my father’s manic episodes I'm afraid there will be nothing left to ensure their livelihoods.