I agree with Dedham, my son asked to be paired with a Mechanical Engineering Cadet and someone on the Rifle team, while he was paired with neither, he was escorted to several Engineering courses and labs, got to speak to the instructors (who showed a genuine interest in him as a person and as a prospective cadet) and he was taken to the Rifle coach (who allowed him to observe and even participate some). The point is that they will TRY to accommodate your requests. Our son contacted his Admissions Officer about the pairings.
I hope your son learns a lot during CFAD. My son's experience could not have been better. The Academy, the instructors and most of all the cadets are professional, helpful and welcoming. Good Luck!