The interpreter's reaction was certainly more spirited compared to your typical Western one:

He told the BBC that during the event, he had had a breakdown, and started hallucinating that angels were coming down into the crowd.

"I started knowing that I am not real, because it's not something possible. But believe me I saw them coming on stage.

"From that moment, it was not myself," he said, saying he had becoming concerned for the safety of people in the stadium and was "absolutely" aware that he was not signing correctly.
His employer, SA interpreters vanished. It is interesting to note that he was employed before in some occasions by the ANC, in which 'nobody complained' about his capabilities, which is rather telling about the quality of internal processes. How he could get his security (and professional) clearing for the funeral is matter of SA state affairs so the ANC can't comment on it. Which is of course fully understandable since the two are obviously clearly distinct entities.