Most portfolio books are simple black books with pages where you can slip materials under plastic (some you mount, but at plastic is easier, and things can be moved more easily).
It sounds like his experience and interest are in the area of Technical Production.
Photos of things he built, or helped to build should be included, and he should practice talking succinctly about what he did exactly, and how much autonomy he had in terms of how to build what was built. Meaning did he read plans and build from those, did he have to create the plans, did he work with a team, or was he the one primarily responsible, did he lead the team, or was he led by a team leader.
If he has any process shots, those would be helpful to include. If he does not, and will be working in something this fall, he should make sure to take process shots to demos rate the steps to the finished product. This will help him talk about the process.
Photos of shows he has lit can be included. He should be able to discuss his role… if not the designer was he the Master Electrician (leading others), or one of the electricians.
In terms of sound it is difficult to communicate that on paper, but if he ran live mix with mics, or ran playback for shows, even a pictue of him behind the sound board could help open up that conversation. Maybe next to his picture he could include the shows on which he has worked sound and his primary responsibility.
If he has any paperwork… hand or computer draftings that he either generated himself or that he had to read in order to build, those could be included by the photographs of the completed set.
If he has light plots, cue sheets either that he created or worked off of, those could be inclued by photos of the productions on which he was involved in lighting.
Same for sound cue lists.
Depending on what he includes, and how many different jobs he did on the same show he may choose to organize the portfolio by show, and talk about all the different things he did on a particular show, or by area… (scenic, lighting, sound, etc…)
Practicing talking about what he has highlighted in the portfolio, and being comfortable answering questions about the work itself, why he wants to study Technical Production, and what some of his possible post graduation goals may be, will help him to feel more confident going into the portfolio review process.
Is there a professional or community theatre close by, or a college department he will not apply to where he can (1) get assistance putting together his portfolio, (2) practice the interview?