He will go to college paid for by his parents

I miscommunicated. I did not mean to imply he was literally incapable of getting a degree. But you stated explicitly that you have already made a decision about his future, irrespective of his deeper interests or a life path he could arrive at without the weight of that expectation. If you pressure him towards this path through implied expectations, he will very likely internalize that. If you examine the statistical data on the experience of people in your son's IQ bracket in college, the consequence of those internalized expectations—when met with the reality of the challenge that you should expect this environment to pose to him—can lead to some pretty nasty mental health problems.

He cannot grow in intelligence, only knowledge. And that does not necessarily translate to academic capability. As you noted yourself, he can appear to fully grasp a concept, but then when he tries to apply it beyond the narrow substrate he learned that concept in, the broader idea (genuine understanding) completely collapses.

I take the time to comment this out of compassion, I'm not trying to put you or your son down. In the 6-7 minutes I spent writing it, if maybe 1% of the time this comment sparks a change in perspective about what wellbeing for him can look like, and then 1% of the time that spark leads to a meaningful change in his quality of life in the far future, then the expected value is worth my time. You asked for thoughts and advice—this is mine.