How can I recover monies owed from the IRS after receiving Release of Tax Lien?

May 2012 IRS receives monies through sale of property; receive letter "cert of tax relief". August 2013 taxpayer representative begins reconciliation of taxpayer account and is TODAY CURRENT, and in good standing with the IRS. TAXPAYER IS DISABLED WITH EARLY ONSET ALZHEIMERS, A CONDITION that had began affecting her mentally a decade earlier..ALL INFORMATION ON FILE WITH THE IRS and, can be PROVEN in a court of law through medical records and employee records. I, the taxpayer's representative have COMPLETED DUE DILIGENCE and can provide details in full if asked... The taxpayer is guilty of FAILURE TO FILE RETURN. Taxes were paid- w-2 forms, IRS transcripts! all prove this. Power of Atty on file If they had filed married filing jointly, taken ALL reasonable deductions, would have received a refund EACH YEAR in question... Taxes were based upon married filing separately, which doubled the tax burden it seemed.... I have a detailed one page spreadsheet of the numbers involved