I agree, I think this bloke definitely deserves the highest award. As an example, a policeman who was caught up in the Iranian Embassy seige in the UK wrestled a gun off a terrorist and was awarded the George Cross. Pretty much the same thing. Not sure what the Australian equivalent is, but the GC ranks equivalent to the VC, except it awarded for acts not in the face of the enemy.
The very special history of the Victoria Cross, means the Victoria Cross was retained as an identical medal with identical standards - technically it's now the Victoria Cross for Australia, but it is treated exactly the same including by the Queen and other Commonwealth governments (New Zealand also has an identical Victoria Cross for New Zealand, and Canada has an almost identical Victoria Cross for Canada - the only change they've made is the motto 'For Valour' is now 'Pro Valore' in Latin, because they felt that in a nation with two official languages, that was appropriate).
All other decorations were replaced with Australian equivalents (although Australians who previously earned a British Honour keep it, and the British government and the Queen can still bestow most British decorations on Australians). That's why the Cross of Valour (CV) ranks alongside the George Cross - because it is the replacement for the George Cross in all particulars, and the GC had that status.
There is some talk that our current government may seek the Queen's permission to create a 'George Cross for Australia' in a similar way to the VC. I'd support that, but I also think the CV is a suitable replacement if that isn't done.