He might have been moved to either Hollywood or Oakwood Cemetery in Richmond. Some Georgians were also reburied at Laurel Grove Cemetery in Savannah. There are Confederate mass graves at all these cemeteries.

I have a book on Confederate dead at Hollywood Cemetery, entitled Southerners At Rest. It lists an Isaac H. Wiley (b. 1831) of Co H, 11th GA, as having died on 1/14/1863, and as being buried in Section SS in an "unknown" plot. Maybe Isaac Wiley was a brother or cousin of your ancestor, since both were in the 11th GA. The author, Chris L. Ferguson, is considered an expert on Hollywood Cemetery and may be able to provide some information on possible burial locations for your ancestor. He and I worked together on some 50th Georgia burial locations.

Good luck!