If some mob shows up and is intent on breaking into my house, with my family in it, they get one warning, in the form of one shot into the crowd. If that doesn't work then I'll start emptying mags, I don't want to hurt anyone, but I'll have very little sympathy for a crazed mob with my family's or my well being at stake. If its my neighbor then things get a bit complicated, I'd have to seriously study the situation and make a decision. I don't think I'd allow them to be hurt, if I felt that was the case I'd intervene, but I wouldn't compromise my safety or put myself in a legal situation to save a neighbor's car. It's easy to say 'they're on their own' but you got to remember the women folk and kids, and how you going to carry that neighbor dieing because you didn't want to open yourself up to legal liability. It's probably easy to say that living in Texas, so I can understand if you feel differently. Rocks through window equals shot, Molitov bombs equals shot, and hurting my animal property equals shot. But mob standing outside yelling isn't code black.
And the story doesn't say why the mob is assaulting this fellow, or I missed it. I'm sure your law in Australia are alot like UK, defend yourself and its life in prison.