As the coursework proceeds, the initial designs and design developments will involve continual assessment by the student with modelling and testing as the final solution evolves.
Presentation skills to be built at this time in addition to modelling in card, foam and wood are formal drawings (Isometric and 3rd Angle Projection), freehand sketching and computer programmes (2DDesign, ProDesktop and GoogleSketchup).
In the first place, have a look at the exam specification for the course at AQA.org.uk and see that the coursework is worth 60% of the overall subject grade. Secondly, ask to see the folder of work as it develops, and encourage well-presented work. It should be A3 Landscape in format. There also may well be opportunities for you to give feedback and opinion on the designs which can be included in his development process. Ask too about deadlines! These will be crucial to a successful project.
As the exam season approaches the teaching and learning will change emphasis to broaden understanding to include industrial processes, mass and batch production methods and Quality Control.
2DDesign and Prodesktop software is available for your son to load onto the home computer and GoogleSketchup is free from the internet.