I am the sole agent under my mother's durable power of attorney for finances. One of my brothers is demanding that I give him all kinds of details on the financial transactions I do for her. I believe it is because he does not trust me and wants to give me a hard time. Do I have to give him this information?
To know whether you are legally required to provide financial reports to anyone, including your brother, turn to the power of attorney document itself. You do not have to make reports unless the document explicitly requires it. If the document is silent on the matter, your brother is out of luck unless you choose to share information with him.
However, you might want to take a step back and assess whether you should extend an olive twig in your brother's direction. Imagine how you would feel if the ledger book was solely in his lap instead of yours. Depending on your situation, you may wish to soothe your brother's mind by sharing financial details with him. Even if what you are doing is right as rain, you may look suspicious and somehow devious if you squeeze him out. If you choose not to share and your brother truly believes you are doing something illegal with your mother's finances, he will have to turn to a court for help.
No matter what the power of attorney document says about making financial reports to others, you do have a legal duty to keep accurate and separate records for all transactions you make on your mother's behalf. Act responsibly and keep careful records -- whether you expect anyone to see them or not.