kid who was in hospital with severe concussions and skull damage, but an examiner came into the hospital to make him take the exams
That is absolutely riduclous, VCAA expressively states in their exam guidelines they
do not expect students to sit their exams against specific written medical advice (that is medical certificate by a qualified doctor which clearly says "x cannot sit their exams due to x in my clinical opinion-or however the doctor chooses to word it). [Exemptions from exams also exist for those experiencing emotional/personal trauma such as the death of a loved one in the immediate lead up to the exam. [I'm not trying to belittle what you said, I just think teachers shouldn't be spreading false rumours about VCAA rules and/or exaggerating situations to scare students].
VCAA employ many procedures to deal with students whose performance may be effected due to unavoidable medical/personal issues. If it is an ongoing issue to which you believe special arrangements can be made to rectify the situation, or reduce the disadvantage, you can apply for special examination conditions to the VCAA (speak to your VCE co-ordinator at school as soon as possible if you want this, as the normal application time for special arrangements is finished, although it is still possible to arrange them if need be). For example, without knowing the specifics of your condition and speaking as an example only, special conditions can be arranged to allow you to have something to eat mid-exam to ensure your sugar levels don't go low.
If you suddenly get very acutely sick on the day of the exam you can apply for a Derived Examination Score where VCAA uses all the other data available about your performance to determine an exam score for an exam you didn't sit. Speak to your VCE co-ordinator for more information about this again.