My brother and I were named POA for our Mom.
My brother and wife complain that they need help, but will not use her money to hire providers to help them.
They also will not allow me to take her to my house.
He says we both must agree because both are POAs.
Do not pay for your Mom's care -- this is what she saved her money for. Care is very expensive and financially unsustainable for adult children to be paying for it.
Why won't he allow you to take her to your house? This may be a blessing since providing hands-on care may eventually become overwhelming to you/your family depending on your Mom's issues.
If your Moom is still competent I would encourage her to go to the attorney and amend the PoA arrangment so that you and your brother don't have the same responsibilities.
It sounds as if his goal is not your moms care but protecting his inheritance.
I almost think I would back off and sent a letter to the lawyer and to your brother that you are withdrawing from POA.
If you can not provide what you think is the best care for your mom, the safest care then you are not doing your "job" as POA.