Medicine at USyd is a graduate-entry undergraduate course, not a postgraduate course.
Each year, about three dozen students enter via the provisional pathway, which requires an ATAR/UAI of 99.5, a semi-formal interview, an audition, and taking HSC music subjects in secondary school for the B.Mus./M.B.B.S or an ATAR/UAI of 99.95 and a semi-formal interview for all other combined medicine programs (B.Sc.(Adv.), B.A.(Hons.), B.Com., B.Eco., B.Med.Sci.).
And no, there are no bonus point schemes for this pathway (and the graduate-entry one, which involves doing passably well in university studies, an admissions test, and a multiple-station interview). If there were, it would reasonable to expect that they increase the threshold for admission but that's not possible. In any case, bonus points would mask the truly brilliant and also dilute the meritocratic means by which the best are admitted and offered scholarships recognising their hard work.
See
http://sydney.edu.au/current_students/student_administration/admissions/eaps.shtml and
http://sydney.edu.au/current_students/student_administration/admissions/broadway_scheme.shtml for two schemes that might apply to your cousin. Maybe he/she shouldn't look to do medicine or medicine via the undergraduate-entry pathway or medicine at USyd.
Just remembered that there are provisions for ATSI students, provided they take the B.Sc.(Adv.)/M.B.B.S. or M.Med.Sci./M.B.B.S. courses. The university and federal government are trying to address the shortage of ATSI medicos. I've stopped reading the med school alum mag or keeping up to date with everything, but there may be something for graduate-entry ATSI guys too.