Q. Am I legally able to claim them then?
A. No. Even if neither the mother or the boy friend are claiming the children, you still need form 8332, from the mother (custodial parent), in order for you to claim them. Even then, you can only claim the child tax credit (before 2018, you could also claim the exemption").
Q. Can my sons mom let her boyfriend claim my sons on his taxes?
A. Yes. See other replies for details.
