Sorry to hear about your predicament, dodojojo. I had Power of Attorney (POA) for the financial affairs of my late parents, in their final years of life, in Australia. Once I had the Power of Attorney, I went round places like banks and utilities to show them the POA so that they would allow me to act on behalf of my parents. Some places were more fussy than others before they accepted my POA.
What started the POA was when we realized that the parents had been driving an uninsured car and living in an uninsured house, because they lost track of the paperwork. Frightening. Once the POA had been accepted by their service providers, then the rest was plain sailing. I received all their mail and email from relevant service providers, including social security. One of the first things I did was to set up Direct Debit for routine payment of bills. If your mother is short of money, you might pay one or two of her bills for her.
In Australia, there is a POA, and also a guardianship, which deals with health matters. I had just a POA.
On rare occasions, I needed a document from my mother's archives, at her house, and this sometimes was a problem. Is there a relative, or a trusted friend, who lives nearby and, if necessary, can be called on to go to your mother's house, find a document, and send it to you?
Hope this helps.