Informal Claims for refund

client filed the 2013 Form 1040 in July 2019. Refund of $10,000 denied by the IRS.

The client has successfully obtained an Appeals conference by telephone. The client has offered a (tenuous) argument concerning their mental impairment, which seems to be the basis for the Appeals conference being offered.

Has anyone used the "informal claim for refund" doctrine or used a title 28 section 2401 (or section 2501) argument in an attempt to obtain at least a compromise with the IRS at the Appeals level? Or actually filed suit in a federal court of claims using either the "informal claim for refund" doctrine or used title 28 section 2401 as a basis for such a suit?

Whether successful or unsuccessful.

Here is a link to a pro se case where the taxpayer made some progress, however I have not found any conclusion. Perhaps, there was a settlement with the IRS. https://cite.case.law/fed-cl/92/277/

Search the Tax Court data base, look for tax cases - the ones I've read about Medical Impairment
as an exception for late filing are really harsh and unforgiving. You not likely to get sympathy
out of a tax court judge unless you have a medical diagnosis from a Psychiatrist stating
he/she suffers from ______and_______and __________, and could not possibly be
expected to keep records and file tax returns.