Yes he is still a dependent. But he might also have to file his own return. Rules to claim a dependent
https://turbotax.intuit.com/tax-tips/family/rules-for-claiming-a-dependent-on-your-tax-return/L8LODb...
They don't have to file if they only have W2 income under 13,850 (2023) but can file to get back any withholding taken out in boxes 2 or 17. But you don't get boxes 4 or 6 back. If they got a 1099Misc or 1099NEC they have to file it as self employment income no matter how small the amount.
Be sure on their return they check the box that says they can be claimed on someone else’s return.
Filing requirements for a dependent
https://ttlc.intuit.com/community/children-dependents/help/do-i-need-to-file-my-own-taxes-if-i-m-a-d...
This answer has been verified for accuracy by an Intuit expert employee
