I'm not from the US, but I can relate to the feeling of being a bit lost about how to explain your needs. Every vision impaired / legally blind person is different and what a lot of people do not understand, is that your vision can change daily. What is adequate lighting one day, may be slightly off or to dim the next.
Getting an official letter from his eye surgeon/optometrist outlining what he can see, and what his needs are is a document that is always useful.
A Pebble is a very small handheld CCTV from what I understand. I imagine it looks like
$1. You can get different handheld CCTV's that do inverted colours. I have a SmartView Versa from HumanWare. It does inverted colours, has a bit of a bigger screen and will also take photos of things, so for example your boyfriend could hold it over the body part of the dummy take a picture then bring it close to his face to look at it.
Does your boyfriend have access to the dummy for study purposes as well? Sometimes I've found you just have to work 40% harder than everyone else to be at their level - spending a significant amount of time memorizing the various parts using the CCTV, by touch and repetition may get him through.
Don't give up, and get creative. Expect the school/disability services to do what they can, but bring some ideas to the table also. At the end of the day the school wants him to pass and so does he.
Good luck and stay strong and be willing to fight for what you want, but be as adaptable as possible and you should see results.