There is no such thing as someone who doesn't get math. Instead, it is the teacher who "does not get how to teach math".
I have come across many very good teachers, and the thing that differentiates them from the less amazing ones is this: they do not have a single "tried and true" method. The teachers who do have this type of "tried and true" method always find problem students, and those students get discouraged. However, those students need to know it is not their fault.
When teaching Multivariable Calculus this past semester, which is infamous for failing engineering students at Cornell, my fellow teachers came from different backgrounds. The less experienced ones would always complain about their students "not getting it" and it was because the teachers themselves did not understand the material to a depth that they could explain the math in multiple ways to students.
In my experience, I have not found one student who cannot grasp a math concept. They may not understand it the normal way- but everyone has a different learning style just like everyone has a different personality. All I do is think of multiple ways to understand and explain every concept, so if I have the pleasure of teaching a student who "just doesn't get it", I can really make a difference in their lives.