You do not need a power of attorney. A power of attorney is not effective in Illinois upon death and cannot be signed by the decedent. You need to be appointed administrator of his estate of executor if he died leaving a Will. The Court will then provide with Letters of Office which will be the document the IRS will need to see when you prepare his final return. Any refund will be made payable to his estate. There may be less complicated and less expensive methods depending on the size of your son's estate. You should talk to a local attorney. Feel free to contact our office, as we have an office in Virginia, Illinois which is approximately 25 minutes from Springfield.
This response is being provided for information purposes only and does not constitute an attorney client relationship. Furthermore, I am only licensed to practice law in the State of Illinois. While there are oftentimes similarities between States' laws, there can also be large differences. You should not rely on this response as legal advice and are highly encouraged to speak to an attorney licensed in your State for an accurate legal answer.
You cannot get a power of attorney as your deceased son cannot appoint you. Also, powers of attorney terminate upon death. You may need to open up a decedent's estate for purposes of filing taxes. I do not know if the IRS will accept a small estate affidavit, even if the estate qualifies for one. It would be a good idea to consult with a probate attorney who handles tax matters for decedent's estates.
The answers you have received are accurate, but it also seems to me that the representative you spoke with at the IRS may have misunderstood. You may want to contact the IRS again regarding options, search their website or consult an experienced accountant or tax professional as I believe there are simple ways to file a final return for a decedent, although a refund may create more of an issue.
The scope of this space does not afford an opportunity to adequately advise you. The response provided is intended to be informative, but not final. You are advised to arrange a consultation at which all facts and documents can be explored and terms for representation agreed. An attorney-client relationship must be formally established.