Ask him

 

"If not MIT, do you still want to do CS?"

If his answer is affirmative, then he does not have a problem. Make up a list of schools with MIT on top. Visit each during the summer. He might just change his mind about which school he wants to go.

If his answer is negative, then his love of CS is not real. Need to find out what is actually motivating him.

His current mindset indicates that he doesn't know what is out there.