First, we are so sorry for your loss. You can file your brother's final tax return on his behalf by creating a return in his name and mark in the My Info section of his return that he is deceased. See the sample screenshot below.
Per the IRS, court-appointed or court-certified personal representatives must attach to the return a copy of the court document showing the appointment. And for the signature on the return, the following is required:
- If there's an appointed personal representative, he or she must sign the return. If it's a joint return, the surviving spouse must also sign it.
- If you're a surviving spouse filing a joint return and there's no appointed personal representative, you should sign the return and write in the signature area "Filing as surviving spouse." A surviving spouse can file joint returns for the taxable year in which the death occurred and, if the death occurred before filing the return, for the taxable year immediately before the year of death.
- If there's no appointed personal representative and there's no surviving spouse, the person in charge of the decedent's property must file and sign the return as "personal representative."
For more information: https://www.irs.gov/taxtopics/tc356
https://ttlc.intuit.com/replies/3300219
