Is this for college application? I think

it is not so "bad" to have a few not so good grades during freshman. Not sure you want to draw attention to this, as long as the grades are not a majr flaw. Based on your description of your son's essay, it sounds a great essay to me. For example, it talks about your son so it is relevant (who he is). Also according to you, it is moving so it will most likely stand out. His stats are already available to the admission officers.

Just my two cents.