I was deemed the custodial parent through department of revenue?

he never filed for custody never filed for visitation i let him see our son as much as he liked we let him move in with us because he lost another job and had no place to live it was a nightmare he failed drug test for work and he smoked pot in our home told him to get out he refused we told him we were leaving 2 months prior i informed the department of revenue of our moving now he has filed for custody in florida