He was a widower, have no idea of any surviving children.
As to the flag, perhaps his obituary might provide some information. Otherwise, one could believe it
might have one time resided at the custom's house where he served as the Harbor Master.
Another place to check would be the Citadel military academy.
As to the 1st South Carolina "One flag survives, Confederate Relic Room, Columbia, South Carolina, Dedmondt also provides information about the final set of colors, in the section on the Fourteenth S.C. Other flags associated with the early units are also covered.
Dedmondt, Glenn, The Flags of Civil War South Carolina, ISBN NUMBER 1-56554-696-2"
I wonder if his book discusses the fate of Charles flag?