Yes, he should file a tax return. in part to document the ability to contribute to a Roth. The IRS is going to look at whether he performed adequate services (not just doing chores) for the $6,000. How many hours did he put in during an average week?
As to whether he is an employee (W-2) , or an independent contractor (1099-NEC), that depends upon how much control you exerted over his work. If a contractor, he is subject to 15.3% self-employment tax.
Fund Your Child’s Roth with Chore Income – Marotta On Money
