"01/03/23 is the date of the (3) bonds that were redeemed. There were (3) bonds redeemed 08/01/22 and (1) bond redeemed on 09/29/21."

From TD: "By continuing to hold the bond, you can continue to postpone reporting the bond's accumulated interest for federal income tax purposes until you redeem it, you transfer the bond to another person, or the bond stops earning interest. When EE and I Bonds reach maturity, they are automatically redeemed and the interest earned is reported for federal income tax purposes."

If your taxpayer left everything in Dad's name until now (which would be an error), that doesn't relieve him from reporting the interest on those 1099-Int. We know it isn't the dead guy reporting that.

"Since the interest was not received until 2023, can I include all the 1099's on the 2023 return."

But your due diligence revealed annual earnings.

"The son told me he left the funds because he didn’t need them"

Now we know more facts. "All  the transactions on Treasury Direct are dated 2023" isn't the case.