My Nephew has just taken the AFQT. How do I convert the categories into Air Force categories?

AFQT : officer qualification test?
If the officer test, not a lot to convert as I recall. Admin for pushing paper, Flight skills and Navigation. Actual officer job assignment is not as straight forward as enlisted so speak with an Officer recruiter.

When I was working on a package for warrant rotary wing aviator the recruiter used the DMDC website to retrieve a REDD (Reenlistment Eligibility Data Display) report that quantified my ASVAB scores for all service requirements. He should be able to do this and then view cutoff scores in the AF enlisted classification directory (Google). He does not have to join to know what he is eligible for, but he would have to go to MEPs to ensure he is not physically disqualified from anything through PULHES requirements like depth perception, color blind, flat foot.

Anyhow, until this kid takes the second oath at MEPS, he isn't obligated to serve

Seems like BS to me

I think it may be best to visit the recruiter with your nephew. It is possible that the information he is relaying to you is being taken out of context.

The percentile scores for each section of the test (Mechanical, Admin, General, Electrical) will determine which jobs the person has the APTITUDE for, however what he or she is QUALIFIED for depends on a number of other factors (Physical, mental, security clearance, etc).
In general, a percentile score above the 75th percentile will guarantee that you can get any job on the list. Then it comes down to those other factors. In the end, the best advice I can give is this...have the individual do their research on what they want to do!

When I enlisted back in 1987, I had very specific goals in mind, so I went looking for a specific type of job. Since I was trying to get into the Air Force Academy, I wanted a job that was not Career Job Reserved, minimally manned, or difficult to get a transfer out of....I needed something that was abundant and easy to be released from. I took a delayed entry administrative job (702X0, mainly for the ability to time my entry to align with the admissions process), to ensure I would A) not be in tech school forever, and B) would be able to be stationed anywhere, and C) NOT be mission critical when the time came to release me to go to the Air Force Academy. I also had to do all of the research on how the enlisted application and medical procedures were administered so that I would know when my recruiter was trying to BS me into changing to a harder to fill position.
SSgt James Atkinson's post below is a great example of someone who knew exactly what they wanted, and did all of the research BEFORE showing up to the recruiters office. If the individual can walk into the recruiters office with all of their ducks in a row, know exactly what jobs they are not only physically and mentally, but aptitudinally (is that even a word?) qualified for, it will make the entire process MUCH easier, not only for the person, but for the recruiters as well.

Good luck, and hopefully the individual will get exactly what they are looking for when joining the military. It is not a glamorous life, but it is a supremely satisfying one, if you go in with your eyes open, and your goals and expectations set to get what you want out of the experience!

As a former USAF RIC, the Recruiter is playing games. Ask him for your nephews MAGE scores and then look up the jobs on about.com. M=Mechanical A=Administrative G=General E=Electrical. The jobs are a first come, first serve basis and change daily, and sometimes by the hour. There is a difference between being Qualified for a job and being able to get said job. The reason why there are a lot of "Open X" jobs, is that it is hard to fill/project said jobs so a kid doesn't have to sit around waiting for a class date to start.

Go to the recruiter and ask him to pull his scores for you to review. Take your nephew. If you need help figuring it out contact me through Rally Point & I will help you. I still have some contacts in AF Recruiting and should be able to help you out.