Can I be paid for preparing records for tax returns and providing them to the accountant?

What I was told by my mom’s estate attorney years ago, was that any family member who did things for my mom in a professional capacity that they would otherwise bill if she was a client, could be paid.
So if your a CPA, you invoice mom just like you would do for a client as your usual rate, say 1040 filing rate is $450.00. If your an RN and make $ 85 hr & you accompany mom 4 hrs for medical appointments, you can invoice her $340.00. If your a interior designer ASID and bill $2500 for staging a property, you invoice her just like you would any other client. All $ is reported income by you. But you have to do whatever in your existing established professional capacity.
But If you work retail or are school teacher or don’t work outside of the home, whatever time & $ spent is done for free out of a sense of familial duty. You might be able to write off mileage for medical appointments if a dependency exists.

Building on what Country Mouse has written. Do not wait for the 'Estate' to pay you. If you have POA, and there is a clause for paying you for your services, then you should be paid now, based on the wage in the POA agreement.

My POA for Mum, uses a certain dollar amount over minimum wage, as opposed to stated a hourly rate in the document.

I doubt you would be reimbursed at your professional wage, as you are not performing you profession. And I doubt that saying you are losing billable hours would fly, as most of us have to organize our tax documents outside of business/work hours.

Do you have power of attorney for the person you're doing this for? And if so, have you read through the documents about it?

It is quite possible that the POA specifies that you should be reimbursed for expenses, which may include loss of earnings, and/or paid at an hourly rate for certain tasks. If so, if there's anything like that, it's straightforward: you create an invoice and claim the money.

If you do not have POA... hm, interesting, I don't know! Who mentioned the advice to keep records of your time and eventually submit bills? - anyone who's actually in charge of the money?