I think that I would go see the Recruiting Area Commander (now Company Commander) and ask for a sit down explanation as a “concerned parent”. The recruiter can set this up for you and can do it at the area office or at your home. Just ask for an explanation of your options. The area commander (usually a Captain) will be able to give you the straight scoop. I was an area commander on Long Island, NY (Suffolk County) and I spoke to many parents over my 2-years in recruiting.
Here are some things that you should know:
1. Retests on the ASVAB rarely produce more than a marginal improvement over the initial score. There is some risk that the score will actually be lower on a retest. If Matt scored a 48 or 49, he might be able to move up a category. If he scored a 40, it is unlikely that his score will improve by 10 points.
2. Here are the ASVAB Categories: The overall score indicates where the applicants stands as a percentage of all test takers. Matt scored in the bottom 50% of everyone who has taken the Armed Services Vocational Aptitude Battery (ASVAB) test. The test is geared to measure “aptitude” not intelligence. There is a difference.
Cat I – 93-100
Cat II – 65-92
Cat IIIA – 50-64
Cat IIIB – 31-49
Cat IVA – 21-30
Cat IVB – 16-20
Cat IVC – 10-15
Cat V – 0-9
3. There is no inherent advantage to anyone to push Cat IIIB enlistments (what you called “beta” enlistment). Emphasis on quantity over quality ended back in 1978. It has been well documented over the years that Cat I-IIIA High School Graduates tend to stick longer and do better in the military. Cat IVs tend to have problems with discipline or adaptability and have generally been barred from enlistment over the years. Cat IIIB’s could go either way – depending on their attitude.
4. Qualification for a specific job in the military is not based on the overall ASVAB score alone; but is also focused on one of the nine (9) sub-test areas within the ASVAB.
GS – General Science
AR – Arithmetic Reasoning
WK – Word Knowledge
PC – Paragraph Comprehension
AS – Automotive & Shop
MK – Math Knowledge
MC – Mechanical Comprehension
EI – Electrical Information
AO – Assembling Objects
5. The individuals Physical Profile (PULHES) from the physical examination also figures into the process. The areas evaluated are: P=Pulmonary, U=Upper Body, L=Lower Body, H=Hearing, E=Eyes, and S=Psychiatric/Psychological. Yeah, I know but P was already used one.

. Top score is 1 in each area. Top profile is 1-1-1-1-1-1. This is known as a "picket fence" profile. Many jobs in the Army require a picket fence.
6. The recruiter can tell the applicant what he MAY or MAY NOT qualify for in terms of specific jobs; but has NO role in the actual job assignment process. This is done by an entirely different person, a Guidance Counselor, at the processing station who is not even in the recruiting chain of command. Until Matt sticks his hand in the air and swears the oath of enlistment, he doesn’t have to agree to any job assignment.
7. Many recruits have unrealistic expectations as to what jobs they can qualify for. Everyone wants to be a helicopter pilot or mechanic, dental hygienist or brain surgeon or some cushy job with lots of technical training on missiles, computers, or electronics. Point of fact is that the sheer number of those jobs is very limited – probably less than 5% of the Army. Most of the jobs in the US Army are in Infantry, Armor and Artillery. That is where the most jobs are – that is no big secret. Since you are in Missouri, Matt may want to consider Engineer, Military Police or Chemical or even Motor Transport. All of these last four are trained near you at Fort Leonard Wood, MO about 30 miles from Rolla, MO.
As I said at the beginning of this note --- ask to talk to the Area Commander/Company Commander who is the top man for recruiters in that area. Hopefully, he can put your mind at ease. No recruiter wants to send anyone “down range” who is not happy. Deception (your word) can only backfire on the recruiter if allegations of recruiting malpractice arise. No recruiter will put his career "on the line" for the sake of one enlistment.
Bottomline to all of this is that it will all depend on Matt. Regardless of the specific job he picks, he alone will make or break his career. The US Army is a great place to start. He will be better for it. As he displays more responsibility and aptitude, he can move up and move on to different things within his career field. If things don't "click", he can walk away at the end of his enlistment with a set of skills that are in demand everywhere.
Best of Luck to Matt. Hope you get all of this sorted out and that things work out for both of you.
Sorry for rambling on.