How do I get a audit of my mother's finances being controlled by a power of attorney. There's been some financial discrepancy .

It depends on who is the power of attorney.  If you suspect something is wrong, you may have to claim breach of fiduciary responsibility and file a complaint with the court demanding an accounting.  If you think your mother is being taken advantage of, you can always contact Adult Protective Services.  Also, if you believe your mother needs protection, or more care than is being provided to her, you can file a complaint asking to be appointed as her guardian, and take over form the pwerson who was the power of attorney and then demand the he/she provides you with an acocunting of what occurred previously.