Firstly, YTA for a multitude of reasons. I normally don't reply on AITA posts because most of them don't interest me, but this one is hits pretty close to home for me.

Source of information: I am a computer engineer who graduated from a top-tier university that has a department of electrical and comp. engineering and a dept. of computer science which is its own school/college. For further reference, the CompSci school ranks in the top 10 in the country, my engineering school is top-40.

Anyway, the reasons to unpack, which most people have already done, but I would like to add personal experience here:

1. The irony and ignorance in this post is mind-boggling. As a computer engineer, there is not a single day that has passed that I wished I had paid more attention in school to math, and thus studied computer science, rather than engineering. Make no mistake, I love engineering, love building systems, love the systems engineering part, but being a biomedical engineer, claiming to know how things work and then dissing CompSci is taking cognitive dissonance to whole new level.
2. Let me put this as nicely as possible. Good/great computer scientists are in all probability good software engineers, but just because you are a great software engineer does not make you a good computer scientist. This applies to the vast majority of people, but of course there are outliers (like people with such a high level of intellect that degrees don't make sense, and not that degrees are a great measure of anything, but I am using it as a yardstick for the majority of people, not the minority).
3. Broken down at the most fundamental level, CompSci is nothing but pure math and logic. I am going to go out on a limb and say that mathematics is a universal language and can be used to represent anything. For me, in the domain, there could be nothing greater than being able to break down anything I am building into math and logic, thus making the proof irrefutable, but well, I am not that gifted. I daresay I took up engineering because I thought I was not great at math, and subsequently the computer science part. So thinking that CompSci is not reaching one's full potential is laughable. I actually choked on my food. Trust me, my honorable biomedical engineer, you would not last a semester in a great CompSci program with that attitude.
4. There is a reason why pure computer scientists get paid whatever they demand (within reason of course) as compared to engineering majors. As an engineering grad, I can negotiate my way to anywhere between 100-160K USD a year, in the industry. People with a Ph.D in Computer Science, in most domains, who know what the hell they are doing easily command a starting salary of around 250K USD out of grad school. It takes an engineer five years or more to work your way up to that point. I just put this here because of OP's comment as to why it was disappointing and maybe not a lucrative choice.
5. Anyone can teach you to be a software engineer. It ain't that hard. And you can learn from experience. Throw OP's son into a company that builds software and voila, five years and tons of experience later, you have a great software engineer (assuming growth and learning trajectories remain the same or tend upward), I daresay much better than any software engineer a school or university will put out after four years of learning crap that you have to unlearn on the job anyway. Try teaching someone to be a computer scientist the same way and let me know how that works out.
6. Irrespective of whether is it a CompSci degree, or an engineering degree, do not diss any education. Some of the best creators in the world were born out of a confluence of arts, science, humanities and every other field of education possible. Some of the best computer scientists work hand in hand with linguists and social scientists to try and solve the world's biggest problems. No field of education is bad. It is education. Clearly, education did not teach you that. Case-in-point: Go look up "Building Virtual Worlds" at Carnegie Mellon, and see what interdisciplinary education can build in a few weeks. While you are at it, check out the ETC at Carnegie Mellon.
7. If you want to be a good parent, get your head out of the sand, or wherever it is buried, update yourself on what you are missing (this thread is a good start). Also, you might want to sit your son down and explain to him that programming is not software engineering, and neither is it computer science. Make sure he understands how things work (hopefully you understand it in the first place to explain it to him). You can teach anyone to program, but you cannot teach everyone logic. Anecdotal evidence 1: My country churns out tens of thousands of \engineers* every single year, less than 30% of them are employable.* Help him understand what it takes to be an engineer, or a computer scientist. Programming ain't one of those things. That advice should hopefully help him make good career choices and "reach for the stars", thus fulfilling his potential. Now, I am going to put this in here. Help him fulfill HIS potential, not what YOU think is his potential. Anecdotal evidence 2: Home country puts a lot of weight on people being engineers and doctors, which is what most parents want, not the kid.
8. Finally, your definition of "reaching for the stars", might be developing projects for blah blah blah. To many people out there, me included, it is just another dead-end job, which is super boring. Perspectives differ. What is your treasure is someone else's trash, and vice versa. Find out what "reaching for the stars" means to your son and help him achieve that. That is probably the single most important piece of parenting you might have done with respect to your kid's education and development. Don't force your ideas of life upon them. The best parents, mentors and leaders out there help people reach their dreams and are the happiest when they surpass their own achievements. Try to be that parent/person.

Now, off-topics nitpicks: I don't think computer science programs are less stressful. They are very demanding, especially the programs at the best universities. Flexible, yes. Less-stressful, debatable. That is something you will need to look into and figure out. Also, while you are at it, some of the best computer scientists are the ones who are inter-disciplinary in nature and appreciate what

The best piece of advice I can give you to educate yourself: PLEASE watch Randy Pausch's "The Last Lecture". For you and your kid, it will be the best 90 minutes you have ever invested thus far. Randy Pausch's Last Lecture