You attach his estate
Place a lien on his estate
Even with no arrears, at the request of the Obligee.
to the obligee it's owed to.
Only if the obligee parent releases the claim or is deceased.
Back support is owed the obligee parent, however any continuing support can go to the child.
In a case such as this, I suggest that the obligee file an estate claim for the unpaid support.
It goes to the State(s) that referred the case to IRS. The State then forwards the money to the obligee or retains it as reimbursement for public assistance issued.
Either to the custodial parent as the obligee, or to the State as reimbursement for public assistance.
Probably - the support is owed to the obligee (i.e., other parent and/or State), not to the children.
If the obligee parent is deceased or has released the claim, however it must be approved by the court and may not include the interest penalties.
If by "back support" you mean retroactive support (support due for a period prior to the entry of the first order), no. If you mean past-due support (support that accrued as the result of an order), the obligee may file a lien on the obligor's estate. The statute of limitations never runs on past-due support.
It depends on what you mean by authorities. As for filing a motion to enforce, the obligee usually needs to make the request of child support enforcement, however, due to the drop in the economy, and the number of out of work fathers owing child support, there is a severe backlog of cases. see link below