It was a stipend for signing for a job. He actually did not go to work for the company and has since returned the $5000.
A dependent needs to file an IRS form 1040 tax return if his own income meets the filing requirements for a dependent.
A dependent of another taxpayer is required to file his or her own tax return if:
IRS Publication 17, page 89, states that the stipend may be considered compensation.
Compensation
Compensation includes wages, salaries, tips, professional fees, bonuses, and other amounts received for providing personal services. It also includes commissions, self-employment income, nontaxable combat pay, military differential pay, taxable alimony and separate maintenance payments, and taxable non-tuition fellowship and stipend payments.
See also this TurboTax Help.