Hello and thank you for using Just Answer,
Please accept my condolences on the loss of your mother.
If no personal representative has been appointed and there is no surviving spouse, the person in charge of the decedent's property must file and sign the return as "personal representative."
Remember to add the word "Deceased" after the decedent's name in the name and address section of the final individual income tax return. Also, please add the date of death across the top of the final individual income tax return. If the decedent is due a refund, it may be necessary to file Form 1310 (PDF), Statement of Person Claiming Refund Due a Deceased Taxpayer, with the return.
If you are a court appointed or certified personal representative filing an original return for your mother, you do not have to file Form 1310. Court appointed or certified personal representatives must attach to the return a copy of the court certificate showing the appointment.
Please let me know if you need more information while you complete this task.
You also asked when a power of attorney expires, there are different types of power of attorneys and that really is more of a legal question, but, another expert felt they should advise the following:"A power of attorney expires upon the death of the person giving the power of attorney."The expert that advised on that is not an attorney either so if your asking ahd anything to do with something other then filing your mother's final return, talk to your own attorney.
Does an original copy of the death certificate need to be attached to the return?
Not unless the IRS requests it.