S.C. Code Ann. § 32-11-10

If any agent constituted by power of attorney or other authority shall do any act for his principal which would be lawful if such principal were living such act shall be valid and binding on the estate of the principal, although he or she may have died before such act was done, provided the party treating with such agent dealt bona fide, not knowing at the time of the doing of such act that such principal was dead.