Can I file a joint return for my deceased parents if I am only a qualified executor for my mother, who passed after my father?

[yellobranc]

The court never assigned a POA for father because my mother was still alive

[JulieR]

Yes. Per IRS instructions, "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."

Please see the following IRS Tax Topic for more information. https://www.irs.gov/taxtopics/tc356