The student in question is a victim of his own complacency.
From dictionary.cambridge.org:
complacency noun also complacence, disapproving
a feeling of calm satisfaction with your own abilities or situation that prevents you from trying harder:
What annoys me about these girls is their complacency - they seem to have no desire to expand their horizons.
There's no room for complacency if we want to stay in this competition!
From oxforddictionaries.com:
complacency (also complacence) NOUN
A feeling of smug or uncritical satisfaction with oneself or one’s achievements:
the figures are better, but there are no grounds for complacency
