Several points:

1. You don't shoot until you are sure of your target. If you can't see it, don't shoot.

2. The police in South Africa issue licenses to possess firearms. Wasn't he checked? Why was a license issued?

3. Firearms kept in readiness and near at hand (e.g., loaded and by the bed) have been shown, over and over, more likely to kill a member of the household than a burglar.

4. It helps your defense in court if you give warning before shooting.

5. If you have a weapon for "self defense" and use it, you will almost certainly end up in court. At the very least you will end up talking with the police.

6. Six years seems like an awfully short sentence.