I believe that
@A1Janitor and
@jbm2m are spot on. The best predictor of future academic success is past academic success and 90% of an engineering education is hardcore academics. Engineering programs and colleges/universities want their students to be successful, but they can't guarantee it. They will give a student ample opportunity to switch majors, like after the first Calc exam. ROTC programs are a different story. Check out threads regarding their policies on switching majors.
My comments are based on the experiences to two DS's. Both were academic superstars- 800s on Math SAT, finished College Calc 3, while in high school, etc.
DS 1 (AROTC) enrolled in Big 10 U Chem E against the advice of his academic advisor. Prior to college he spent his free time doing everything other than
engineering EC's. He could do proofs and reactions in his sleep, but could barely stick two legos together. It took him about 30 min. to realize that he hated the engineering part of engineering. There was no room in his schedule for CS and foreign language classes. First chance he got he changed his major to Chemistry and was happy as a clam. That academic freedom literally made him the the Army officer he is today. Less Q (Bond Reference). More Milo Minderbinder.
DS 2, on the other hand. loved building things. The first thing he ever bought with his own money, at about age 5, was roll of duct tape, which--along with toilet paper and paper towel rolls he scavenged from the garbage--he made a gun. By high school he was making potato guns. Most important, he could withstand the tedium of the Mech E curriculum which his older brother could not. He now works for a company which builds the very complicated machines/systems and is very demanding of his attention to detail.
In each case, their ECs were a good predictor of future career success, but had little to do with their academic success.
Wish you the best of luck!
Edit. Forgot something.
DS 1 was active in academic competitions--Math Counts, State Nat Geo Bee Champ, Quiz Bowl, Science Bowl. This would be a good place for your DS to concentrate energies. Aside from what looks good on the CV, it's an excellent place to learn to perform under pressure in front of an audience. Every question you get, every time you buzz in represents a 5 foot putt to win the hole.