As noted by Mr. Zelinger, the POA ceased with death so it is no longer in the picture.
In TN, court approval is required to sell a decedents real property in almost all cases. The exception is if the decedent left a will and that will empowered the executor to sell real property without ourt approval.
The reason the court must approve is to protect beneficiaries and creditors of the estate. They want to make sure the sale is for a fair price (as opposed to an inside sale for way below market value) so the estate can pay its debts and/or other beneficiaries receive a fair share.
This answer does not constitute legal advice nor form an attorney client relationship. I am not your lawyer. If you have a legal issue in Tennessee you may contact me for a free consult.
I am not a TN attorney or an expert on TN probate procedures, but I can offer this. The fact that there is or was a POA is irrelevant now that the person has died. It would appear that the sale of the house is an estate matter and therefore a probate matter. One could reasonably guess that the court must approve the sale so that the executor is protected as are the beneficiaries that this is a fair sales price and that the sale of the house will appropriately benefit the estate and therefore the beneficiaries (it is for the protection of both the estate/executor and beneficiaries). I might add that the heavy-handed nature of some state's probate proceedings is the reason why many people are choosing to use revocable living trusts to dispose of their property as these arrangements typically negate the need for a costly probate hearing to approve the actions of the estate representative.
This is not legal advice nor intended to create an attorney-client relationship. The information provided here is informational in nature only. This attorney may not be licensed in the jurisdiction which you have a question about so the answer could be only general in nature. Visit Steve Zelinger's website: http://www.stevenzelinger.com/
Jon is correct. Unless the will is very specific regarding the sale, authority, etc., the court will have to approve the sale.
LEGAL DISCLAIMER-An attorney can only give you competent legal advice if he or she knows all the facts and is licensed to practice law in the state specific to your question. The comments above are not intended to be legal advice but general comments based on the limited information provided in the question. I am only licensed to practice in the State of Tennessee.