Sending a 5 page resume is not the ideal - if he is still applying to other schools, have him pare it down to no more than 2 pages (that is all most people will bother to read). He has a chance, the engineering internship will be a plus along with other activities showing he’s well rounded. Given an IB diploma, he should have the appropriate course work. IF he’d like to better his chances, he can retake the ACT at TAMU without waiting for a test date. This may sound crazy to many people, but computer programming & english are shockingly similar subjects- that may be a unique but good choice for his recommendation provided it focused on the correct skill sets.
Thanks for all of the information! @RMNiMiTz I was hoping if you clarify how “borderline” my DB is in? Is he borderline accepted or borderline rejected?