After you file

You would have to amend the previous years.   Didn’t the 1099NEC income show up on Schedule C?  Did he have a Net Profit or a loss?

 

You pay Self Employment tax (Scheduled SE) FICA on a Net Profit of $400 or more on Schedule C in addition to regular income tax on it.   You pay 15.3% SE tax on 92.35% of your Net Profit (If it is greater than $400).  The 15.3% self employed SE Tax is to pay both the employer part and employee part of Social Security and Medicare.