A search of the National Archives of SA data base using the terms Abraham AND David AND Theron found 9 documents
It looks like Abrahan David Stephanus Theron applied for naturalisation in 1899 and died in 1838 and was, as you say married to Emma Christina Faldt..
There is an earlier Abraham David Theron who died in 1826 and a later one who was still living in 1956 and possibly still living in 1977 (or that is yet another)
1)DESCRIPTION APPLICATION FOR LETTERS OF NATURALIZATION. ABRAHAM DAVID STEPHANUS THERON. 1899
2)THERON, DAVID ABRAHAM. EN VILJOEN, GEERTRUYDA CATHARINA. TESTAMENT 1814
3)DESCRIPTION THERON, DAVID ABRAHAM. WILL. 1814, filed 1826
4)VILJOEN, GEERTRUIJDA CATHARINA. WIFE OF DAVID ABRAHAM THERON. WILL 1814, filed 1826
5) Not relevant
6) THERON, ABRAHAM DAVID STEFANUS. SURVIVING SPOUSE EMMA CHRISTINA THERON (BORN FALDT). 1938
7) ILLIQUID CASE. PAYMENT. SQUIRE FINANCE AND INVESTMENT CO. (PTY.)
LTD. VERSUS ABRAHAM DAVID THERON. 1977
8) DESCRIPTION THERON, EMMA CHRISTINA. (BORN FALDT). 1966 Predeceased spouse ABRAHAM DAVID THERON.
9) DESCRIPTION ILLIQUID CASE. DIVORCE. MARTHA ALETTE THERON (BORN KOTZE) VERSUS
ABRAHAM DAVID THERON.
STARTING 19560000
ENDING 19560000
REMARKS CASE WITHDRAWN.
If you haven't already found it you might find this thread about Emma Faldt useful http://www.rootschat.com/forum/index.php?topic=726392.0