I'm sorry to hear of your mom's problems. Unfortunately, this is not unusual. Older people with dementia often revert to their older memories and lose many of their recent years. It's sad that the congregation isn't more help, but this too is not unusual. They take, take, and take, but individuals who have faithfully served and contributed for many years are quite often left by the wayside when they fall into hard times and need help themselves.
I hope the Social Services folks do a thorough job of investigating the suspicious transactions. If it turns out the JW in charge of her estate was helping herself to some of the money, please try to get her prosecuted to the fullest extent of the law. At the very least, make sure her deeds and the fact that she's a JW gets publicized far and wide. The more dirt thrown on the Borg and J-Dawg's name, the better!