My mother has dementia and my brotherinlaw and sister are I believe stealing from my mother, I have had to beg to the guardianship board for funds for her medical care, there is money missing and they are secretive and furtive and not transparent. They have discredited me and treat me badly, iI am the only one helping her , they are the financial administrators and have changed the bank accounts to their names, there lifestyle is lavish and extravagant and I don't believe that they could afford this, they retired early and travel widely 20 to 30 trips per year and are involved in about 8 committees, I can get the proof of this lifestyle but it will take time and my mother is frail,
2. How is the guardianship board involved? Is there a guardian, or is it your BIL and sister, since you write that they are the financial administrators? Or are they handling your mother's affairs pursuant to a DPOA?
3. If they're the guardians, and you have proof that they're stealing, contact the court that appointed them guardian(s) and ask for an investigation.