Unfortunately there are very few doctors in the world who have ever treated patients with SCLS -- especially successfully so. Therefore, it's most unlikely that anybody will know of anyone who is qualified in South Carolina -- never mind in Charleston.
What you father should do is get his current doctors to put together and give him all his medical records, so he may take them with him wherever he goes, and then to refer him to a competent and compassionate physician, preferably a specialist in internal medicine or immunology affiliated with a major university hospital -- in this case, with the Medical University of South Carolina, the state's #1-ranked hospital.
As a start, his current doctors could contact the Division Director of Internal Medicine, Dr. William P. Moran, tel. 843-792-5386, and/or Dr. Richard M. Silver, the Director of the Division of Rheumatology and Immunology, tel. 843-792-1991, to have him seen once he gets to Charleston.
What your father needs to find is a doctor who is willing to (a) do his/her homework on this rare disorder (namely, read the literature and follow the instructions), and (b) consult with the few SCLS experts available: in the United States, Dr. Mark S. Pecker, _mpecker@med.cornell.edu_ and Dr. Kirk Druey, _kdruey@niaid.nih.gov_
Good luck!