What you describe is consistent with the Indiana instructions.
Indiana IT-40 Full-Year Resident Individual Income Tax Booklet, page 7, here states:
Signing the Deceased Individual’s Tax Return
If a joint return is filed by the surviving spouse, the surviving spouse should sign his or her own name and after the signature write: “Filing as Surviving Spouse.”
An executor or administrator appointed to the deceased’s estate must file and sign the return (even if this isn’t the final return), indicating their relationship after their signature (e.g. administrator).
If there is no executor, or if an administrator has not been appointed, the person filing the return should sign and give their relationship to the deceased (e.g. “John Doe, nephew”). Only one tax return should be filed on behalf of the deceased.
The Indiana Department of Revenue may ask for a copy of the death certificate. Keep a copy with your tax records.
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