yes
The fathers financial responsibility to his children does not end because the courts have decided that custody should go exclusively to the mother or others.
If the custody order is done through a court of law, the sister will receive (and needs) child support.
There are lots of factors involved. What does the court order say? If there is back child support owed, it is still to be paid. The child still needs to be supported, in this case the state may take the money and give it to the foster care or new guardian for the benefit of the child.
I believe your ex would collect it
no see links
By listening to an attorney telling him not to try. see links below
That would be a person whose parental rights have been terminated.
Whoever gains guardianship.
Unfortunately, this depends on gender. Hen mothers lose their parental rights, usually due to a conviction of child abuse, than no. But, when that happens to a father, than yes. Even in cases where the single mother loses her rights, the child is placed in foster care, and the father pays child support without having access rights, though he was not involved in the abuse. That's the case with a KCMO father right now who daughter called him when her mother killed his son last May. The girl is in foster care 250 miles from here and he's paying for it. For three years he's been trying to get custody due to her mental illness which has been documented by the police.
Child support is for the custodial parent.Be warned though that courts have ordered custodial fathers to pay when the mother make considerably less. This is most common in California.
Does it matter? Society does not need another fatherless child adding to the crime rate. see link below
If it is your child then you do not need to be held responsible. You are responsible.