That's one of the ways people use "him". Other times, they use "him" to mean that the individual in question is male.
These days, "her" to combat the implicit assumption that people must be male is common enough, it's almost safer to assume that "him" means someone who is specifically male.
I think this is not true yet. Anecdotally I personally only noticed this first a few months ago and no one I've discussed it with in real life has yet known what I'm talking about.
The story refers to the article, the student, in the masculine form. In English, we do not have explicit masculine/feminine forms of adjectives, therefore the article, in this case a student, is a male as the story's author referred to the article as 'him', 'he' and 'his'. I simply do not understand what you are finding so hard about this, other than petty political correctness. QED.
Furthermore, it is totally irrelevant to the story itself!
You. Are. Wrong.
Now, we're more using "her" for "person of unspecified/unknown gender", but the problem remains: We've got three states (male, female, and unknown/unspecified), and only two words (him and her). No matter what, there's going to be this kind of problem, until we come up with a third word. (People have suggested "they" or "them", but I don't like it because of singular/plural issues.)