Pistorius, his uncle Arnold says, is a broken man.
"What can you say if the person you love the most dies, and you were the instrument?" he said in an interview with CNN. "How would you feel? It's unthinkable."
Arnold Pistorius said his nephew is housebound, especially since an attempt to go out in public in April ended in backlash against the once-celebrated "Blade Runner."
The Olympian shot and killed Steenkamp early February 14 and is accused of murdering her. He claims he thought she was a burglar.
Pistorius is due in court for a hearing next week. A trial date has not been set.