cannot be
I doubt there were many child support laws back then. Normally, only the custodial parent of the child can file for child support, not the actual child.
yes
Yes, they can. n
Yes.
Can I get a Twic card owing back child support
your State's child support agency
what if your done with current child support but still owe interest for back support.
No, you are not responsible for their back child support.
Yes, if a parent owes back child support, they will have to pay it until it is zeroed out even when the children are grown. The age of the child does not affect back child support at all.
Back child support is paid until paid in full, regardless of the age of the child.
or any child support obligation
No. The money isn't for the mother. The money is for supporting the child. Back child support belongs to the estate of the deceased and will eventually benefit the child. And even if the child should die, the back child support does not go away.