Firstly, age is the least of his worries. He should move on from the thought of that being a barrier.
I honestly don't think there is an option for him that doesn't include at least starting, and possibly finishing, and doing well in a new bachelor degree. There are 'shorter' pathways (such as doing a Grad Dip/Cert at Flinders) but I'm not sure that his GPA of 2.5 would get him into one (plus they are very expensive and typically FFP) and non-standard entry (see below).
Given his history, I would be very wary of recommending a return to university for the sole purpose of getting into medicine. Even for people with outstanding academic records, the chances are stacked against them. If he were to return to university, then I'd recommend he do so with the aim of completing a career degree (ie. nursing, but there are plenty of other options) then using his results along the way to try for medicine, but knowing that he is (statistically) unlikely to be successful and that it won't all be for nothing as he'll have a degree with good job prospects and opportunities at the end of it.
In fact, there are universities (including UTas, but also others) that offer nursing as a 'fast-track' degree, which means he could have it completed in two years and either be moving from that to medicine (if very fortunate) or moving into a nursing career. If he was fortunate with medicine, he could also then use nursing as a way to support himself while he continued studying.
For example! As I said, there are other career degree options.
For non-standard entry, he could use a single year GPA from a new degree and a UCAT score to apply. If he was successful first go, he wouldn't need to finish the new degree and could switch straight to medicine. This is BEST CASE scenario (time-wise) and not particularly likely for a number of (mostly statistical) reasons.
For graduate entry, he'd need to finish the new degree and sit GAMSAT.
The other big issue may be the academic integrity breach. I honestly have no idea what the long-term repercussions of this are (if any). Perhaps someone else can weigh in on that part.
biom perhaps (due to teaching experience, not actual experience, just to be clear!)?
ETA: I am interested to know what degree/result he used for his Masters application, as I wouldn't have thought his academic history at the end of his BSc would have been competitive for post-graduate level study.
ETA2: I've just had a look at UTAS' academic integrity info and it looks like the worst case scenario for the highest level breach is a 6 month exclusion from the university. High level breaches were things like fraud/forgery and contract cheating (paying someone else to do your assignment/exam). It looks like your friend's breach would be considered intermediate at UTAS which would result in the fail and having to complete an academic integrity module before continuing studies. This doesn't seem like it would be a barrier at all to re-embarking on future studies.