^ If his wife does live there and uses the car though she could import it in her name.
Just be aware that the Australian government enjoy nothing more than taxing people as much as possible and will make sure they get lots of money out of her when the car lands. My favourite is that they ignore what you paid for the car and instead require you to get the car valued to determine what the car is worth in Aus which is most likely more than what you would pay in Japan... They then take that value as the basis to apply lots and lots of tax; GST, Duty, Luxury car tax... So quite quickly what could ahve worked out saving you money may end up being no cheaper.
I saw an article a while ago that showed the price of an SLS AMG in Australia.... Almost $123k of the $497k you pay goes to the government rather than Mercedes!
http://www.smh.com.au/executive-style/motors/luxury-cars-why-do-we-pay-more-20110419-1dml9.html