Can’t the basic standard be met either by CS or foreign language (since it says ‘or’ in the requirements)? So the second high school requiring foreign language meets the standard. BTW, that second’s school requirements seem more in line with what selective colleges are looking for.
Also I believe diabetes can be classified as a disability, meaning your son can take tests untimed if needed, especially if he has to mange his disease hourly as you say. This way he can take his medicines during the test and not worry about it. Talk to your school about that if you need it. And colleges would not know it was untimed as that would violate the ADA.