If you are preparing a return for her, please explain what you are trying to accomplish. 2022 would be the last year that a tax return is required for her.
In particular, income in respect of a decedent (IRD) refers to untaxed income that a decedent had earned or had a right to receive during their lifetime. IRD is taxed to the individual beneficiary or entity that inherits this income.
https://www.investopedia.com/terms/i/income_respectof_decedent.asp#:~:text=Income%20in%20respect%20o....
