I - who lurks here frequently but never posts - felt so strongly about your question I went thru the password reset nightmare just to share what has proven to be the best bit of coaching ever given to me on this topic.
I am 57, FIREd at 52, and had the technology existed my father would have written the exact same post about me in 1985 while I was studying Computer Engineering at the University of Illinois. I thought I wanted to develop bionic limbs (from the $6M Man generation
and so was taking a nightmare schedule of EE, CS, ME and Chmn courses. Along the way I discovered that I was no longer the smartest guy in the room, nor on the block, and while I could learn anything- I couldn't do it anywhere as quickly as a lot of other people. Basically I had too short an attention span to crank thru 5 pages of equations without missing a negative sign somewhere and frankly had no desire to spend the rest of my life in that endeavor.
After a semiconductor physics exam in which I got a 42/100, I went to the professor and basically core-dumped... asked him if he I thought I should give up. He starting laughing and shared that a 42 was the 3rd highest score of the semester. I noted that being the 3rd least incompetent engineer wasn't really a marketable skill and he said "you don't really think we expect you to get all those answers in 3 hours do you? We are looking for you to prove that you understand how to take what we teach you and apply it to what you will experience in the real world". IT CHANGED MY LIFE FOREVER. He taught me that Engineering school isn't about what you learn, it is about LEARNING HOW TO LEARN and RATIONALIZING PROBLEM-SOLVING. Few other majors do this.
I graduated BSEE, a decade later got an MBA in International Finance and ended up living all over the world running large sales organizations for technology companies. Patents? Nope. Elon Musk? Nope. But understanding technology and how to apply it meant really talented engineers wanted to work for me and clients wanted to buy from me. My engineering training was my super-power; 5 years after graduation no employer gave a damn about the degree; they cared about how it shaped my brain and what it could do for them.
Right or wrong the first half or more of engineering school is really about weeding people out... I saw plenty of guys sharper than me fail. It is a sick game. Plenty of your son's fellow students are having the same doubts, they just don't have the balls to admit it.
An engineer can be a businessman, but a businessman can never be an engineer. I hope my story helps in some way.
If you have got this far, a final tidbit for your son to read. Sooner or later he will take a class called TAM - Theoretical and Applied Mechanics. Almost 40 years later I still remember the final exam. One question. 50% of semester grade. It went like this:
At t=0 a tank is driving down a winding road (data provided about road). The turret is revolving (data given) and the gun is going up and down (data given).The gun has a shell (muzzle velocity etc given) Atmospheric and weather data provided. A duck is flying in a parabolic arc from A to B (data given)
FINAL EXAM QUESTION: When is the first time, in seconds, that the gunner should fire the shell in order to hit the duck.
The whiz kids panicked. Those of us who demonstrated how to logically break it down, discuss the relevant issues, and set it up in a form that could be arithmetically solved at some point - carried the day.