Congrats to your son for being prevention focused at a young age!
My DH is similar in stats- he is 5'6, 165, and 36 yrs old- but he has HUGE frame- i swear his shoulders are as wide as he is tall
He is VERY active and very muscular- so he enjoys things like sweet potatoes, fruit, oatmeal, and occasional garbage. I would say he is reduced carb, not low.
I think the suggestion to include foods like fruit and sweet potato or squash is a good one. Even with diabetes in family, i would think such a diet would not effect his blood sugar.
Getting tons of blood sugar readings won't really show much at his age.....it takes a long time to damage the metabolic system enough for that to happen.....yes, it is possible, but it is fairly unusual (there was massive concern regarding pediatric cases of type II around 2008. as it turns out, it is very, very rare- BUT we are seeing a huge increase in relatively young, obese adults developing it....basically, it takes awhile to really destroy your body in that capacity).
I would think borrowing a meter from a relative a couple times a year for a fasting glucose would be sufficient to keep an eye on things.
I would also urge him to keep on BP- it is another part of metabolic syndrome, and causes many diabetic comlications like kidney disease and damage to retina. It is easy to have it checked at gym or grocery store
Great job providing lists for him! Don't forget to include which drinks are low carb, foods to order at a sushi place/pub/whatever types of restaurants he normally goes to with friends. I'm guessing he is single from your post? Young guys aren't going to order a salad on a date or when out with friends
You might want to suggest easy things to throw in his bag, if rehearsals go long-- low sugar jerky, nuts, fruit, prepackaged cheese like those cracker barrel to go ones.......