My brother is POA my father died in July 2017. My mother is in a nursing home with dementia. I have a feeling he is taking large sums of money for him and his family. Do I have the right as I am getting 1/3 of funds as stated in my parents will to see how he is spending their money?He is an alcoholic, forgetful, not trusting.
Have a look at your state/county website and see what you can find out about reporting suspicions of financial abuse of vulnerable adults. You don't have a right to see your mother's accounts, but there are people in authority who do provided they have grounds to demand them - it's a question of rootling out the right ones.
Oh, btw - put all thoughts of your ⅓ funds out of your mind. It has no existence until - spit spit spit may she live forever - your mother passes on. I know you only mention it in the hope that as a potential beneficiary you might have more leverage (you don't, not at this point); but if it's seen as your motive for acting it will win you no friends with the powers-that-be.