Hi, My mother is 81 and since my father died circa 3 years

Hi, My mother is 81 and since my father died circa 3 years ago my brother BDS LLB is, I believe, her power of attorney. My late father told him to look after my mother's affairs which I am happy with and we both share looking after her day to day needs as she is still fully independent and living in her own home. I know she has a will and her estate which is of a rel small value (max 200k) is to be shared equally amongst 3 of us (we have a sister in the US) Unfortunately I do not speak with my brother and I would like to gain access to her will , also i am concerned she is showing minor, early signs of age related dementia although sub clinical at minute. How do I preveny or ensure fair play if she is to deteriorate through time as it saddens me to say but I do not trust my brother compounded by his knowledge of the law although he doesn't practise as works in his first profession. can you advise me of the steps I have to take to ensure full transparency in this matter. diana BDS

 I am unaware if he is a welfare attorney or other . will the property be shared equally as in will or will he have power to change a will??