Yes, if he claimed your child as his dependent when the child didn't qualify as such, the IRS may penalize him for the unauthorized decrease in tax he reported on his tax return. Also, he could be fined for filing a false tax return.
You can claim your child as your dependent on your tax return if you are entitled to do that. You will need to mail your return in however. The IRS will straighten the matter out later when they do an investigation and if it is determined that you are entitled to the dependency exemption, you will receive it.
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