"and had a part time job and received a 1099-NEC with box 1 being the only amount."

In other words, he worked. What he did is offer his services. He is his own business. Whether he is misclassified and should be on payroll with W2, or is running a sole proprietorship and files Sched C, is yet to determine. But even you called it "a" "job" and that means business and that is Schedule C at the least.

NEC = compensation for services rendered.

"They do not own a business."

They are the business. That's pretty much the definition of Sole Proprietor.