Yes, he will have to note, on his taxes, that he is being claimed by someone else.
There is a rule that says IF somebody else CAN claim him as a dependent, he is not allowed to claim his own exemption. If he has sufficient income (usually more than $6300), he can & should still file taxes; he just doesn’t get his own $4050 exemption (deduction). In TurboTax, he indicates that somebody else can claim him as a dependent, at the personal information section.
Even if he had less, he is allowed to file if he needs to get back income tax withholding. He cannot get back social security or Medicare tax withholding.
