It would depend on the evidence that was available to be admitted during the trial.
But certainly if one were to apply what's proposed to be the new law of self-defence here, the first question would be, did he have a reasonable perception that he was about to be attacked? That would be the first question. So his subjective beliefs there obviously are the most relevant place where we start.
The next question is really whether a reasonable person, with much the same background as he has, in that same situation would have had the same sense that an attack was coming.
The second element of self-defence would be, did he act for a defensive purpose as opposed to another purpose? Was he seeking revenge or was he seeking merely to protect himself? That would be the relevant question.
There is a third issue the court would have to examine in that case: would the reasonable person say that the steps he took in these circumstances, given everything else we know—given his beliefs, his fears, and all the other factors—have been reasonable? Fortunately, we get to leave those decisions for the people who hear the evidence.