my son is going to the 485

interview,what does he need to bring? i got my conditional green card first last year, for some reason, my son just received his interview letter, but my citizen hu*****and will be out of country for a meeting at the interview time, do i need him go with us or only me can bring my son should be fine? my son is 10 years old. on the letter it does not mention my hu*****and must be there. i really don't want him miss the work. has anyone experienced the same situation before? thanks for any reply, waiting for it.....