Can I press charges for my parents for credit card fraud?

My brother claims that our father who is an 89 year old Alzheimer's patient, in a moment of lucidity, gave him permission to use his credit cards. He said nothing to our 86 year old mother, but took my Dad's cards and charged up about $10,000. My mother doesn't want to get my brother "in trouble", is there anything I can do on her behalf? I have already taken steps to make sure that this doesn't happen again. Thanks.