Even though I normally would urge learning the foreign language in your son’s particular case I’m leaning to just letting him take the courses in his area of interest and finding a list of colleges that won’t care about the missing language courses. FWIW, a college language course will probably move at about twice the speed of a high school course.
I am wondering though what the rush is. Might it not be better to just take the extra year to finish high school and use the summers to explore his interests? Maybe take some computer science sooner and make sure this direction makes sense?