This person lacked empathy and sensitivity, but at the end it sounds like he learned from his mistakes.
It is hard to empathize with people who work less hard on understanding the programming topics, that occur at work, deeply.
You are describing lack of empathy and sensitivity...
Empathy isn't easy. It shouldn't be easy. It is a skill like any other skills and you must consciously train it to be better at it.
This person lacked empathy and sensitivity, but at the end it sounds like he learned from his mistakes.