When your mother moves in to your house, it is usually done to help your mother out. This often includes taking care of her physically and taking care of her finances. You pay her bills and take her to the doctor. You do all of this because you love her. Then you start hearing from a sibling or two that they think you are taking advantage of your mother and they want to see all her bank statements so they can track what you have been doing.
Utah does have a set of laws that deal with elder financial abuse and certain persons are obligated to report any suspected activity. Your siblings may just want to make sure mom is being protected rather than gathering evidence to report a crime. You should, however, be careful when meeting with them. Make sure no one is recording the conversation and that you are clear and forthright. Better yet, get an attorney and have them review the bank statements and prepare your response to your siblings.
The key is be transparent with your mother’s finances. You have to make sure that each transaction you do for your mother is documented and can be explained without context. This means that it should be obvious that it was an expense for your mother and not disguised as your taking advantage of her finances. Keep records and receipts. Think of it like being audited by the IRS. The more you can document, the better off you are!