The question, "What level of math is programming roughly analogous to?" isn't necessarily answerable. However, you've provided context so if I can be allowed to rephrase the question as "What level of maths is required to create a standard CRUD platform (language not relevant)?", it would definitely be algebra.

Sure you might be able to do it with a knowledge of nothing more than basic arithmetic, but you're going to be able to understand and manipulate data more efficiently with a solid understanding of algebra.

That being said, Objective-C isn't the easiest language to pick up, especially as a first language. If your 11 year old starts to struggle, maybe point him at something like Python which has a shallow learning curve, great support (especially for beginners), and can do pretty much anything (ignoring the argument of whether it _should_ be used for things like drivers).

If your son chooses software engineering as a career. Advanced calculus may well be required. I've had to debug complex legacy code before that implemented computations rooted in calculus and without that knowledge, I wouldn't have been capable of succeeding.