Commercial & ATPL Theory.
Pity your son is not in Sydney. If he were, I would recommend the NSW TAFE in the city. The course is 18 months to 2 years taught by professionals who are both pilots and academics. They have been teaching theory for more than 30 years and they have some connection with either Sydney University or the University Of NSW. One of which has its own flying school.
You will also find that the time he has spent at the TAFE will get him credits, if at some time later he wants to convert his Advanced Diploma to a Degree.
There is also a TAFE college based at Parafield (Adelaide), the course is run BY the TAFE I think its called Regency TAFE do an internet search.
Swinburne Uni in Melbourne runs a very good course, the course content can be viewed on the net. However the CPL & ATPL theory is out sourced.