Is this brother the PoA for your Mom? If so, he gets to call the shots if your Mom is impaired or incapacitated (as per the PoA document).
If you are not sure if he is her PoA and it is active, your only recourse is to have an experienced elder law attorrney right up a letter that threatens a guardianship fight in court if he doesn't come up with proof of his active PoA.
Or, if you suspect she is being abused or neglected, you can report her as a vulnerable adult to APS. BUT if APS doesn't find evidence to support your claim, then your relationship with this brother will get worse if that's even possible.
He probably has his reasons. They could be bad or crazy reasons, but still reasons to him. What is your best guess as to his reasons for not letting his sibling visit mom? Better yet, ask him why.
If you are not sure if he is her PoA and it is active, your only recourse is to have an experienced elder law attorrney right up a letter that threatens a guardianship fight in court if he doesn't come up with proof of his active PoA.
Or, if you suspect she is being abused or neglected, you can report her as a vulnerable adult to APS. BUT if APS doesn't find evidence to support your claim, then your relationship with this brother will get worse if that's even possible.
What is your best guess as to his reasons for not letting his sibling visit mom? Better yet, ask him why.