Hi Knowsnothing,
As a non-jw I cannot give detailed advice, but I've been in a couple of very stressful family situations. If your objective is to get through to your mother, it might help to slow things down a little. That would give you more time with her real personality, and hopefully reduce the chance of ultimatums resulting from the great stress you both feel.
Perhaps say that you want time to consider what the elders have said, and also time to talk it through with her. Be affectionate and reasonable. In discussions, take one topic at a time, and research it carefully first. I found jwfacts a great resource.
Best wishes to you in this difficult time. I respect your integrity and hope the situation turns out well.
Retro