Software engineering, as a career, is a bizarre one; it is simultaneously one of the highest paying entry level jobs and also one of the communities that doesn't really care about your academic background (to a degree). Placing into a software engineering role at a "FAANG" company (short for Facebook, Apple, Amazon, Netflix, Google - but really just a euphemism for high-paying, high-prestige tech companies) - typically requires nothing more than an ability to navigate their bizarre interview process, which looks like this:
1. Get noticed by their resume/cover-letter algorithm, or know someone on the inside who can refer you
2. Successfully navigate their coding challenge games (see
https://leetcode.com/ for a taste)
3. Be able to describe computing systems on a white-board
4. Be able to talk intelligently about theoretical systems face-to-face with another human
5. Be patient, have humility, and be willing to repeat 1-4 OVER AND OVER AND OVER
If you can do 1-5, regardless of your academic background, you can be successful in software engineering. (By the way, you should by this book for your son as a gift:
https://www.amazon.com/Cracking-Coding-Interview-Programming-Questions/dp/0984782850)That's software engineering. It doesn't matter what degree is has as long as he can do 1-5. Period.
Now, the question is: does he want to do software engineering? We are about to enter into a cool new world where fundamental computing systems are about to get much more bizarre; Moore's law is essentially tapped out for simple architecture CPU's, so we're moving to complex compute architectures for specific applications: chips designed for AI; neromorphic processors, complex system-on-chips sponsored by DARPA... it's getting interesting. Also, we have a political push to bring back manufacturing domestically, to wrestle the grip that China has on our supply chain. There is about to be a huge demand in this area, specifically in the USA. If any of _that_ sounds interesting, then I think getting into computing may be more of a payoff than computer science.
Oh, and you can always follow-up your BS with an MS, online from a number of the top ranked schools, to cover his basis.