The school will more than likely have some sort of insurance option that he can take, along with possibly adding you on.
See what your job offers though, as that will probably be the cheapest option. I am covered through the school's plan here (not cheap, but an incredible plan) and it would be quite a bit extra $$$ to add my wife on. So she has hers through her job since they pay for most of it, if I added her on we'd be paying it.
So you'll just have to see what the school offers and compare it to what it would cost to possibly add him on to your plan if you get one through work. Some schools may even require him to be on their specific plan, just to insure that each student has adequate coverage, so he may not have an option.