Agree with this guy. As a contractor, there really shouldn't be any expectation of long term work. You don't need to teach this guy how to develope, just how to maintain your system. That's it. For example, companies buy MS Office all the time, then hire some guy to maintain the entire network. As opposed to pay microsoft to send a guy out from time to time. Microsoft and Cisco etc, have certification standards so that dumbshits can't just say, "oh, I got this" with absolutely no clue. This reduces the risk of dumbshits tarnishing their companies name when said product fails to work. Basically, they wan't you to give this guy a YOURNAMEHERE certification.
I do think you should get some reimbursement for any extra time you spend training this guy. Or you could try to offload some of the tedius tasks onto him and finish ahead of schedule, assuming you're paid for the job rather than the hour.
I'm pretty sure that they never intended to keep someone that charges as much as you in the long term. You're expected to find other work at your level until they need something new developed. And if your last job looked shoddy because some kid couldn't maintain it, you aren't getting the next one from this company. Why does microsoft keep in business even with windows 8? Companies don't need a hot shot developer to to maintain it, just some kid fresh out of college will do.