^Actually, his summer shouldn’t be spent working/learning all day long, but should be spent doing activities, since THAT too is part of the questions he may have for college admissions (he could ride his skateboard, go to the pool/the beach/the lake, it doesn"t matter as long as it involved non-competitive fun.) It’s also important for appropriate development and just normal for kids in the summer!
Reading 5 books of personal choice (fiction, non fiction, comics/graphic novels) is recommended.
Check out if there’s a NASA summer camp in Houston.
Also
https://www.tacc.utexas.edu/education/stem-programs/camp-c3
https://cns.utexas.edu/fri/outreach/164-freshman-research-initiative/outreach/633-shadow-a-scientist-program
https://www.idtech.com/locations/texas-summer-camps/austin/id-tech-texas-hillel/