" I have worked in taxes over 30 years and only found out about the widower filing status allowed for 3 years even though there was no dependent when I attended IRS training to be an IRS volunteer tax preparer."
Not sure who taught you but the qualifying widower status is for only 2 tax years after the year of death when you can still file a joint return. And you still must have a qualifying dependent for that status as well as for HOH filing status ... read up on these rules in the IRS pub 17. The first 2 days of the H&R Block basic tax course teaches filing status and dependents so I don't know where you learned to do taxes and missed these very important topics that are the first two chapters of the Pub 17 which is the basic textbook for any tax pro.
Form the pub 17 page 25:
If your spouse died in 2021, you can use married filing jointly as your filing status for 2021 if you otherwise qualify to use that status. The year of death is the last year for which you can file jointly with your deceased spouse. See Married Filing Jointly, earlier. You may be eligible to use qualifying widow(er) as your filing status for 2 years following the year your spouse died. For example, if your spouse died in 2020, and you haven't remarried, you may be able to use this filing status for 2021 and 2022.
