No, he can't
Spouses cannot be claimed as a dependent. If the spouse (you) had zero income, he could claim your exemption as if you were a dependent on a married filing separate return. He cannot claim your son as a dependent if he lived with you for more than the last half of the year.
Since you have already filed your tax return, his return would be rejected if he files trying to claim you and your son as a dependent.
If he tries to claim your son as a dependent by mailing his return, the IRS may require you both to provide documentation. The IRS would review the documentation and determine who gets your son as a dependent. If this happens (and maybe just in case) you should gather the following documentation:
- Rent receipts
- Utility bills
- School records for your child
(if applicable)
- Doctors notes, or a pastors
note.
- Notes from neighbors, or third
party people that the child lives with you
- Anything you can come up with
the proves the child was with you.
