Mystery author, you have such a marvelous way of writing that every sentence is vital to the story as a whole.
Harry has always been very aware of Severus. He's obsessed to the point that it is clouding his mind, well when it comes to his friends. What he gains is pivotal knowledge of what's bee hidden from him.
Harry going into the shadows of his mind and engaging Severus was was amazing. A relationship developing in that manner through the remnants of Occlumency lessons was very clever.