I dont know the law, but given the opportunity I hope,I would have done exactly what this man did.
The only reason this man is alive is because the thieves couldnt shoot well. In my mind that means he has every right to try to kill them.
I carry, so I run through scenarios in my mind as to what I would do in different situations. You have to take your local laws into consideration. In this case, being where I am I would have to let them pass unless there was an immediate threat to me. It would not be worth going to jail for.