This young boy has a very inquiring mind. Explaining why punctuation is there and what it does is far more important to him. Then he can work out how to use it himself.
Test it out on your own family you will be amazed at the results. Try to understand their way of thinking. Would you rather write sentences about what you’re interested in, or a subject you hate? You are still learning to write sentences correctly with a capital letter and full stop within your field of interest.