So your son is a freshman in HS?
Is he looking for summer school or some kind of summer program?
If he wants to be an engineer, make sure he is on track with Math to at least be taking Calculus by Senior year of HS.
So he may need to catch up on math if the didn’t take Algebra 8th grade.
I would not worry about Ivy League colleges at this point…no summer program is going to get him into one.
He should be doing something this (and every) summer…working, learning, but not sitting home and playing video games.
Google “high school summer programs near houston tx” and there are many programs. Also see if there are some at your local community college, e.g.
http://www.hccs.edu/district/top-news/hcc-stem-summer-camp-a-success.html