LuciousJ, I sure feel bad about that stuff. I have been there myself with a good part of it.
You know what? I had to read it a couple of times to get it all in! - so this is a person who does Xmas & Birthdays, associates apparantly with whoever she pleases, is not above playing bingo, and has apparantly herself been disfellowshipped...and suddenly snaps in the space of 24 hours???
I am going to put forth a couple of guesses -- no offense, I hope.
1. Somebody in that congregation has gotten to her and is manipulative of her for their own reasons.
2. As previously posted, your mom may be having some delusional thinking which makes her more susceptible to problem #1. The descriptions you have given of her behavior extremems do not indicate anything like rational thought.
We discovered my own mom to be doing stuff kind of like this a few years back - it turned out to be the first stages of Altzheimer's. My sister actually started using the onset of this disease to try to control her life and finances, etc. I am still fighting this one out in court.
When the dust settles a little, it might be good to find out if the other sisters think there could be something medical going on here...