I agree with most of what Mangy Dog says, but I'd have to suggest you avoid TPG like the plague. Misleading plans, pitiful support, wrong-headed DSL infrastructure and invisible proxies (although this last most probably won't affect your client).
In some ways, they're worse than Telstra BigPong (not the support; there is no ISP in Oz with worse support than PigPond - maybe on the planet. I could go on in depth, but another time ...)
Expect to pay
at least AU$60 per month for a DSL connection - any less and I guarantee there is a catch. That will normally only buy you a miserable 256/64 connection, but you can get a 512/128 if you shop
carefully - watch out for 1GB or less monthly quotas.
Last time I enquired, DSL connection times ranged upwards from two weeks. As Telstra owns all the exchanges, this can't easily be reduced. If you're unlucky enough to score a pair-gain line or some other horror, it will take considerably longer. If he knows where he is going to live, I would start organizing things before he leaves the States.
BTW, a fair proportion of lines in Oz will never be suitable for ADSL. You are looking at satellite or ISDN (which is now limited to 128kbps). Or Cable.
If you're lucky enough to have Cable in the street, either Telstra or Optus (most streets are the former, some the latter), you can now get a 5Mbs/128kbs connection for AU$60 per month. Obviously, the 5Mbs is the absolute upper limit and not at all typical.
BTW, that last plan has a quota of 10GB. Telstra includes both uploads and downloads (which is a scam), but many ISPs only charge for downloads. Naturally, if you throw enough money at an ISP, you can get higher performance.
If you get more detailed info closer to his move, such as a suburb, street or ideally phone number, it becomes possible to check availability of different broadband options. PM me if you want assistance - I'd be happy to help.