It is possible he can be claimed as a dependent only
if you file a separate return and in the year of 2016 he:
-had
no gross income,
-isn't filing a return, and
-wasn't the dependent of another taxpayer.
If you were married and filed jointly, you cannot claim him as a dependent, as each
spouse gets a personal exemption on a married filing jointly tax return
which is equal to a dependency exemption.