Hi Einstein ,I got into the accelerated program at my old school (Mckinnon) . Mostly ,all test for admission into accelerated programs are made by the same company called "Edutest" . I made a guide on to get admitted , doing these type of tests which you can check out here
A guide on how to study for the selective schools test(MHS ,Mac.Rob, Nossal,Cory , although it targeted into a year 9 level . So i will chip in few cents over here .
PreparationThere will be 6 exams consisting of Verbal Reasoning , Reading comprehension , Numerical Reasoning ,Mathematics , Creative writing and Argumentative writing .
Verbal reasoning : Practice your vocabulary , because there will be a lot of questions regarding it .
Reading: Basically practice your reading , grammar , and spelling skills .
Numerical reasoning : Practice Number patterns and word problems .
Mathematics: Its good to do some chapter reviews and cylnic revision in your textbook.
Writing : Practice writing essays under a certain time limit . When i did it the creative topic was ,"the box" , and the argumentative one was, "should homework be compulsory " .
As Pi has mention there are some very good books to buy to prepare him for the exam , also kumon isn't a bad idea it will get him to learn the concepts which will be tested quickly and efficiently .
Competition: In terms of competition each exam is broken down into 6 results categories .
Superior=top 11%
Above average: top 12-23%
High average= top 24-40%
Average= top 41-60%
Low average= top 61-80%
Below average = bottom 19%
In conclusion , i hope that helps . Sorry for the brief explanations , about what on each test , i've gone more in depth , in the guide i've linked you .
I hope i've helped if you have any more questions , you can always feel free to private message me or ask them here .
And good luck to your brother .