Below Average performance of an Intelligent HS Junior

Hi, I am writing to get advise from those parents who are struggling or have struggled in past, to guide their below average performing high school boys. My son is very intelligent but has no motivation to do well. He is in an extremely competitive school where he is below 50% in class rank. He hates his school to the core, he can not stand being there or going there every day. He has no friends.
Is it advisable to change school for just one last year, ie. before senior year starts?
His GPA is 3.1 without any significant medals or achievements. He wants to go into business. Does he have chances of getting into a good university?

If you want advice from parents, there is a parents forum!
http://talk.collegeconfidential.com/parents-forum/