I am dealing with the final (personal 1040) tax return (my brother) who died in 2023. In the identifying header, do I enter HIS SSN (which I have) or do I have to apply for new taxpayer identification number and enter that? I have received info that his SSN should NOT be used on the final return as it is now in a 'locked' state with the IRS. Any information would be useful, especially IRS publications or FAQs. Thanks
