Sunset
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
But at the same time, the executor isn't obligated to scour the decedent's past for things that might have been done incorrectly that could result in a liability. The OP can assume that between his dad and TIAA-CREF that the past RMDs were computed correctly unless information comes to his attention that they were not done correctly and the fact that they didn't change isn't necessarily indicative of an error.
I'd let a sleeping dog lie and focus on the balance sheet at the date of death and subsequent transactions.
+1
It is not a debt as the IRS has not sent a bill for it, or even sent anything, as it may well not be owed anything. Don't folks trust our government.
Just as the cable company, Electric company, local grocery store, may or may not send something claiming a debt, but until they do, its not a debt.
Perhaps OP should be calling the cable company to ask them to review their records for the past 10 years to see that they charged enough and were paid enough as well