While the internet provides us with much useful information, it also offers a lot of guesses and opinions.
Have your nephew apply to at least one school he thinks he won't get into; it can't hurt. The only thing you have to lose is the application fee. College admissions aren't based solely off GPA; in fact, SATs, volunteer work and extracurriculars, as well as a successful interview, also put him on the map.
You never know exactly what colleges are looking for so he may as well trust his guidance counselor and apply to a reach school!