Sister with dementia was in a VA hospital awaiting placement in memory VA care. Against the family another sister removed her. Any advice?

The ill sister went missing for several days and when she was found we had her admitted to a VA hospital for exam and evaluation. She had been diagnosed two months prior with profound Alzheimer's related dementia. The doc was willing to admit her pending placement in a VA memory care center as there was no family willing or able to care for her. As these placements usually take time, we felt fortunate that her placement would be a priority as she was in the care of the VA. The first concern of the sister who was not willing to take her was that they would take all of her money. Not an issue as the VA would basically care for her for the rest of her life (age 84). She is a wartime vet and has excellent benefits. She also has no children and has never been married. Against the wishes of all of the family, the sister her voiced concern over $ had her discharged to her the very next day. Access to the ill sister is almost non-existent. When phone calls are made to speak to her the phone is put on speaker. These two sisters have had a contentious relationship for some time now and in the hospital the ill sister said that she would go anywhere but with the sister who took her. She has virtually no short-term memory. However she still knows family and familiar places. She is able to care for her personal needs and is not yet incontinent. All sibling are quite elderly and there are no funds to seek legal assistance. Are there any agencies we could call to check on her and to account for her finances. It is possible that the caregiver sister has obtained POA which would be illegal as she was diagnosed with dementia before all of this took place?