My DS's first choice school is 8 hours away, so he interviewed locally. Since he plays a fall, winter, and spring sport, it would have been difficult ( not to mention expensive) to get down there for an interview. The interview went well and he did send a thank you email. It's always nice to thank someone for their time, so I think that is always a good call. Just have your son keep reaching out to the ROO or PMS at the schools he wants to attend and keep them posted on his application progress, even if he doesn't get a response. At least they will know he is making an effort.
Best of luck!