Carl Pistorius is accused in the 2010 death of a female motorcyclist, Pistorius family attorney Kenny Oldwage said.
Culpable homicide refers to "unlawful negligent killing," South African police say.
Prosecutors say Carl Pistorius was driving recklessly in Vanderbijlpark, South Africa, when he crashed with the motorcyclist in the daytime.
Oldwage disputes allegations that his client was driving recklessly and said the motorcyclist rode into Carl Pistorius' vehicle.