Don't spend too much time on theoretical training. The best way to learn programming is to do programming. If the person is already familiar with C / C++ and have the ability to cope with new technology / language then it won't take much time to learn iPhone programming. At first just train the basics. Basics of Obj-C. Don't go into the details, just the basic syntax (method, class, property, init etc). There are many web resources for it. Just Google for them. Then go to the high level iPhone application architecture (what is the entry point for customization, how the app is started or terminated, event handling etc). Pay some time for MVC and delegate pattern which are widely used in iPhone app. Then some basic development (view controller, IB etc). Apple has excellent docs for the beginners. You can follow them.
And then start CODING, follow the SAMPLE CODES from Apple, GOOGLE when a problem occurred, ask SO.
And when he is familiar with the basics, pay some special time for memory management. Otherwise you may be in big trouble.
During the interview, you should make sure that he is familiar with general programming concepts, familiar with OOP, knows basic algorithms and data structure and must be familiar with memory management without garbage collector.