My brother is Mom's DPOA and he wants us to help pay for her caregiving. She has her own money and investments. Any advice?

Either he has spent her money or he is trying to save it so he inherits something.

You have a right to ask for an accounting. I would do this and if found he has spent her money then its his responsibility to pay for her care.

You know the red flag here is that he doesn’t want to share what he’s done with her money.

Tell us more of the back story.
Who cares for mom? Is she living in her own home? Is the DPOA living with her? I assume you’ve done the math on what you thought she had and about what her expenses are? And how long this has been going on? Is it time to consider filing for Medicaid?

Don’t spend your money on caring for mom. You may need it for a lawyer to get her help.

Tell him 'No'. There is no reason for you to pay anything towards your mother's care. That is what her money is supposed to be spent on.

Now if he is doing hands on caregiving, ie appointments, shopping, has her living with him and more, then it would be reasonable for him to ask you for help with the activities of caring for Mum, or to give him respite, so he can go on a holiday, or just have 1-2 days off a week. You do not want him to get burnt out.

I firmly believed that my Moms money be spent before I put in my own. I am retired and on a fixed budget. When she ran out I and my brothers would have to step in and help.

I would also want to be assured that brother is doing his part financially. Always pay with a check or have the money put directly in Moms account.

I would require copies of her bank accounts and investments before committing to anything. Mom's money should be used for her care until it runs out then look into medicaid or splitting cost with your brother.