What are a Non-Custodial Parent's Rights if the Custodial Parent is Missing

A custodial parent with what is believed to be a worsening substance abuse problem went missing, and has not been seen for a week. The children are presently with the grandparents. The non-custodial parent wants to know if he can simply take the children from the grandparents into his custody, or if he should first go to court for an order. He has already filed a motion to modify custody, but he would like to take custody of the children before the hearing date.

If he has a lawyer helping with the motion to modify custody, this is something that he should discuss with his lawyer.

If the grandparents agree to let him take custody of the children, then it's a non-issue. He can simply take custody and keep the children in his care until mom returns or the court officially grants him primary custody. He can speak with the police in the jurisdiction where the grandparents live, to see if they would back up his effort to take custody if the grandparents say "no", or if they would tell him to first get a court order.