Tax return for deceased relative

 To find out if she filed a return in 2022-2024:

• Call the IRS and be prepared to provide her SSN, DOB, and mailing address. You will need to mail or fax your POA document (Form 2848) beforehand to be authorized. Call 800-829-1040 for further assistance.
• Mail IRS Form 4506 (Request for Copy of Tax Return) to request her 2022-2024 records. You will need POA authorization to sign form 4506 to access her records. 

She may not have had a filing requirement for those years. 

To get a SSA-1099 for a deceased person, you will need to call or visit your nearest Social Security Office. The number to call is 1-800-772-1713.  If you have an office nearby, it may be best to visit to request an appointment. 

As far as the filing requirements for 2025, if the amount of the 1099 R and the taxable amount of her Social Security is under $23,750, there is no filing requirement. To determine if Social Security is taxable or not, there is a specific formula to be used. It is, 

(1/2 of her Social Security) + (IRA Distribution) + (Any other interest/income) = Provisional Income

If the result is $25,000 or less, her Social Security is $0% taxable. You can ignore it completely for the filing threshold. For example, if she got $20,000 in SS and $10,000 from an IRA:  $10,000 (1/2 social security) + $10,000 (IRA) = $20,000. 

Since $20,000 is less than $25,000, her Social Security is not taxable. Her "Gross Income" for the IRS is only the $10,000 IRA distribution. If this is the case, there's no filing requirement.

If all she had was Social Security income for 2026, there is no filing requirement for 2026. If the 1099R was received in 2026, then you would need to use the formula I provided above to determine if there is a filing requirement.