You'll need a bankruptcy specialist for that filing. Elder care attorneys are not bankruptcy attorneys and choosing one to file a bankruptcy would be a very poor choice, and could cost you through the attorney's lack of knowledge of personal bankruptcy issues. Both elder law and bankruptcy are distinct specialties within the field of law.
One way to find an Elder Law Attorney is to go to this link. Scroll down until you see a box where you type in your zip code. That is how I found my Elder Law Attorney for myself and for my parents.
How advanced is her dementia? I ask as it may be too late for POA. Your only option if she is not competent enough to understand "in the moment" what she is signing. Your only option in that case would be guardianship.
https://www.agingcare.com/local/elder-law-attorneys