The IRS audited my deceased dads estate last year, and looks like they want to audit again. How long?
This is just a guess, but I’d say that the trustee didn’t properly prepare the trust’s tax returns when they were due. If the trust has been wrapped up, a final return should have been filed. That would have put the IRS on notice that there was nothing to go looking for any more and would probably have them off of your back now.