OP –
Congrats to your son on having several excellent choices! I think what will make his decision difficult is that you may not be able to visit any of the campuses in advance. In his case, however, I would focus on the likelihood that he will be comfortable and successful at the college. I think this is what most CC posters mean by “fit,” but it may be particularly important to an international student. Here are some questions I would ask in addition to the ones about cost and courses of study:
Is one school particularly good with support services for international students? Any US engineering school will have some international students, but some of the five your list may have better international students offices and support programs than others. You can probably get a sense of this from online research. I would especially check out resources for students who speak English as a second language. I’m sure your son’s English is quite good or else he would not have been so successful in admissions, but living full-time in a second language and taking very technical coursework in it will be a new challenge for him.
Are there other students from your home country on campus? It seems to me that many international students appreciate having some presence from their home country on campus, if for no other reason than to get a break from speaking English all the time.
How important is it to your son to have a familiar community off campus? I am inferring from your user name that you live in Tokyo. Keep in mind that a school in a major city like Chicago (IIT) may give him more access to Japanese restaurants, expats, cultural events, etc. On the other hand, if he really wants to dive into a more “traditional” American college experience, a school like Virginia Tech would provide that. You know your son better than we do, but you can help him think about that.
Is one school better than the others at helping students access US internships or job opportunities? Some schools may have more services to help their international students obtain work visas or other legal necessities to supplement their engineering coursework with work experience. That could be valuable to your son.
I’m sure there are other good questions to ask, and folks here might be able to supplement this list.