Your son also has not presented any of his related coursework from his degree program. Presenting the course names would provide him with the opportunity for additional keywords. Did he complete any major individual or group projects? If so, he can explore those on his résumé too.
Lastly, your son has not taken the time to ensure his résumé was developed in accordance with today’s best practices. Open a current and well-regarded résumé book, or take a look at samples on my website, and you will see his résumé has the opportunity for improvement. From creating an engaging format to building a qualifications summary, perhaps while preparing for those tough interview questions, he can also revamp his résumé to garner more traction. Best to both of you as you navigate this together.