Does he want to be intellectually challenged and just hasn't figured out the right path yet?
If he wants a challenge, it sounds like he should look for professors offering undergraduate research opportunities. It doesn't necessarily have to be directly in CS. I worked with a professor on a polymer chemistry project while earning my undergraduate CS degree. He got someone who could troubleshoot data acquisition hardware and write software for analysis; I got to learn more about chemistry and statistics. It was a fantastic experience.
I was at a small liberal arts college. I would presume that there would be even more research opportunities at a Big 10 university, though I don't know if it is hard to make personal contacts on such large campuses.
My brief advice: don’t try to race through undergrad using the extra credits. Take enough time to explore and digest higher difficulty coursework while maintaining high GPA, goal should be to land in a top grad school. Also, take time for personal learning and development in undergrad. (This means things that don’t result in receiving a grade. Go study abroad or something.) Your kid sounds smart but unmotivated. Finding that motivation is up to them.
Edit: also don’t get cocky. Nothing you wrote sounds particularly impressive to me.
Is he definitely going to the Big-10 university? I almost hate to ask this, but is attending an elite private university an option?
It is very much possible to get an outstanding education at public universities. I went to the University of Wisconsin for my Ph.D. in math, and they have a fabulous graduate program. I know some of the professors there are also very devoted to excellent undergraduate education.
But my sense is that the usual outcome is a good education, and to get a truly top-notch education at a large public university, you have to seek it out. Some people naturally do this, but seeking out opportunities is a talent -- one I mostly lacked myself as an undergraduate. From what I can discern, it's easy to miss out.
Whereas at a private university there will be a lot of peer pressure. I went to Rice as an undergrad, and I met a lot of fellow students who were incredibly accomplished and motivated at a variety of pursuits (academic and otherwise). The peer pressure very much pushed me in the right direction. Although some people don't need this, or don't really benefit from it, I did.
My point is not to say "private universities are better than public" -- there are many excellent public universities, and plenty of mediocre private ones. If the Big 10 place is his only choice, then good luck there -- all of the Big 10 schools are good universities, and some are excellent.
But, if possible, I'd suggest that he be as deliberate as possible in his choice of university. I wouldn't worry too much about whether CC credits will be accepted or not; instead, I'd try to figure out (as much as I could) what the classes are like, and what the student experience is.
I'd suggest that this student find a way to apply what s/he's learned: write a mobile app, a game, a web app, or something like that. If s/he prefers electronics because of the past robotics work, invest in a hobbyist FPGA development board ($119 or so from Digilent), and they can create their own hardware devices.
Education is a very important thing but ultimately it has to be applied in order to be of use. A lot of people who did well within the structured confines of a classroom environment fall down when they reach the real world.
I dropped out of high school at 15 and moved out at 16. Currently 21 and running https://hackclub.com.
I know that when I was in his shoes, I felt like I tried everything to find meaning (community college classes, reading books, learning new subjects, etc), but it took me literally moving out and into a group house in San Francisco to find a community of other people like me (see https://stories.californiasunday.com/2015-06-07/real-teenage... for my story).
I think it's all about finding like-minded peers that push you. If he's into computer science, perhaps there are hackathons near him? Or maybe he'd get value out of our Slack (https://slack.hackclub.com)? We have a lot of students like him in our community.
We put together https://hackathons.hackclub.com to aggregate high school hackathons and https://mlh.io/seasons/na-2019/events is the best resource for college hackathons if it's helpful.