The fundamental question is whether your ex is an independent contractor or an employee.
If your ex was an independent contractor, then your ex is responsible for all of his own taxes. The person hiring him simply pays the agreed-upon contract amount ; If your ex was an employee, then the person hiring him must pay a share of the social security taxes, and possibly withhold income taxes.
It is not possible to say whether your ex is an independent contractor or an employee. I do not see how your ex did anything wrong here -- so long as he pays the appropriate taxes on the money he earned.
Completely agree with Attorney Perry. Hence, this is not an immigration question.
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There are lots of ways to earn income. Some of them are sporadic. If you look at IRS form 1040, there are many categories of income. It doesn't sound like your Ex was an employee so tax deductions would not have happened. He might have received an 1099 at the end of the year but you do not mention it. In this case, there is nothing wrong or illegal going on. However, an honest taxpayer would report that income, most likely in line 21 of IRS form 1040 under other income. Especially if the man that hired your Ex deducted the $600 as an expense. Yet the tax consequences if any is too complicated to discuss here and most likely not relevant in your Ex's case.
Agreeing to work for pay that includes no deductions for taxes is not per se illegal but not paying taxes on that income is. If you believed yourself to be an independent contractor, you are entitled to get paid a gross amount, but you have to account for that income yourself and pay quarterly deposits to the taxing authorities. If you thought yourself to be an employee, you will still have the same obligation if the employer failed to properly retain and pay deductions.
At this point, be sure to report all of the income and pay all of the taxes due. Speak to a tax person about whether you have a present obligation to make any quarterly deposits toward your taxes.
Good luck to you.
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