definitely memorise your syllabus well ahead of prelims, every question they can ask you will be from the syllabus and sometimes the answer will be a straight syllabus dotpoint (in mcq).i dont do business but my brother is next year for year 11, any tips i can pass on lol
i do enjoy business bc it is one of my more rote learning subjects, so id recommend quizlets/flashcards, there are heaps of premade ones by people doing hsc business, so you don't have to waste time making it yourself, like overall id just memorise, rinse, repeat, thats what'll get you the marks.
good luck to him!!