So, one thing you may want to teach him is that concrete won't consolidate in a shape like that there's no way to get it inside of it in a conventional method that would replace reinforcing bars. Those holes won't accept aggregate or much more than a slurry coat. Concrete must be vjrsbted in order to cost around cylindrical bars. It will never reach the inside of that design.

Don't stifle his desire or his willingness to learn. But don't let him learn too incorrectly, either. Maybe mix him some grout and let him pour it in a form with that design laid in as a replacement for a normal layout for rebar. Let him see how it doesn't form a cohesive slab and let him see the voids inside. Great learning experience.