S.C. Code Ann. § 63-15-520: Power of attorney.

If no other parent possesses custodial responsibility under the law of this State, other than this article, or if an existing court order prohibits contact between the child and the other parent, a deploying parent, by power of attorney, may delegate all or part of his or her custodial responsibility to an adult nonparent for the period of deployment. The power of attorney is revocable by the deploying parent through a revocation of the power of attorney signed by the deploying parent.