I suspect almost all of these “overdue” taxes are fictional artifacts of IRS computers that have run amok with zero human intervention.
When my dad passed away, I immediately filed paperwork with the IRS and SS to that effect and another form that said as his estate manager that my only fiduciary responsibility to the IRS for his estate was the year he died and the year after when the estate was being settled.
I didn’t bother filing taxes for him either years because his only income was a small amount of SS and the IRS actually owed him a small amount of one-time-only special Obama stimulous money one of those years, but which wasn’t worth the effort to file for.
For several years after that, the place he had been living forwarded me mail that had been addressed to him, and for years afterwards, I received several letters a year genned up by IRS computers showing that he owed taxes and ever-increasing “penalties” and “interest”. I mostly tossed the letters, but would open one occasionally, and before the letters quit coming, the IRS had him owing them hundreds of thousands of dollars.
The letters finally stopped after the home he lived in notified me that they would no longer forward me his mail. Never heard a peep from the IRS after that. Presumably the post office finally kicked their letters back to them with the note that he no longer lived at that address. Lord only knows what they did after that.
My wife was helping a blind man and he was a nightmare. No money in savings and living off a large pension. Shopaholic. He was in debt to everyone. When he died, we were cleaning the house. One collector called, we told him that he was dead and there was nothing. You could hear him deflate.
The IRS fought the bank for the assets.