First of all, I hope your son sticks it out with engineering. It will be hard work. Engineering students have to take more courses per semester than liberal arts students, and there are a significant number of labs and projects which take up big chunks of time. This will leave less time for some of the traditional school spirit building activities, but in exchange he will receive a base set of analytical reasoning/problem solving skills and the ability to work in teams that can be applied for the rest of his life. If that is coupled with the communication skills and cultural wisdom imparted by the liberal arts, then he will have built a strong foundation for a lifetime of learning and for finding his place in the age of innovation.
In terms of rankings:
Engineers like to create things, so they tend to create their own rankings optimized to their own situation rather than use “off the shelf” rankings. I do not know anyone in engineering who hires based on US News ranking.
Engineers also like to take things apart, analyze them and see how they work (or don’t work). If one looks at the methodology behind the US News Engineering Ranking, it becomes clear that it is a pure poll of people in academic positions who have a vested interest in the outcome as well as little to no familiarity with any institutions other than the ones that they attended. This would suggest that the poll is actually a measure of how many people each school feeds into academia, which correlates more with the size of the school’s Phd program than with the attributes of the undergraduate academic program. A “back of the envelope” correlation analysis tends to support this hypothesis.
Note that if a practicing engineer were to use something similar in rigor to the US News ranking as justification for decision, it would be seen as “career limiting”.
Also note that “prestige” is an irrational construct that has no use in the rational world of engineering. No one in their right mind would fly in a plane whose design was based on the principles of “prestige”.
In terms of reputation:
It is probably best to think of the notion of “reputation” in these rankings as the “reputation within academia” not the “academic reputation”. It is also important to note that industry will use a different set of evaluation criteria than academia and it will vary based on the type of job that they are hiring for. Also note that it is industry, not academia that hires the vast majority of engineers.