He needs to file separately and claim his own income.  

You can still claim if he meets the qualifications below, but even if you claim him you cannot claim his income. On his tax return, he should mark that he can be claimed by someone else.

To claim this family member, he or she must meet these requirements to be a Qualifying Child:

Under the qualifying child rules:

Your qualifying dependent must live with you for more than half the year.

The qualifying dependent must be one of these:

Under age 19 at the end of the year and younger than you (or your spouse if married filing jointly)

Under age 24 at the end of the tax year and younger than you (or your spouse if married filing jointly)

Permanently and totally disabled

The qualifying dependent can’t have provided more than half of his or her own support.