| Quote #4
When the Dementors approached him, he heard the last moments of his mother's life, her attempts to protect him, Harry, from Lord Voldemort, and Voldemort's laughter before he murdered her [...] Harry dozed fitfully sinking into dreams of clammy, rotted hands and petrified pleading, jerking awake to dwell again on his mother's voice. (10.1.5)
In terms of style, Azkaban generally uses fairly short sentences and features lots of dialogue. But we get occasional passages like this, where there are a series of clauses that help to emphasize emotion. Here, we get a bunch of descriptions of what Harry experiences around the Dementors, which emphasizes how his experience is a complex, emotional, and ongoing affair.
| Quote #5
"It has nothing to do with weakness," said Professor Lupin sharply, as though he had read Harry's mind. "The Dementors affect you worse than the others because there are horrors in your past that others don't have." (10.2.31)
Lupin introduces one of the major themes of the book here, as well as an important lesson to Harry – being affected by the bad parts of your past isn't a weakness. And being affected by the past is actually a good thing, since the past shouldn't be ignored. Harry wouldn't be the person he is if he could just brush the Dementors off and go about his day.
| Quote #6
He stopped on the picture of his parents' wedding day. There was his father waving up at him, beaming, the untidy black hair Harry had inherited standing up in all directions. There was his mother, alight with happiness, arm in arm with his dad. And there [...] that must be him. Their best man [...] Harry had never given him a thought before. (11.1.4)
We see a lot of different "artifacts" from the past in this novel, turning the whole thing into an episode of History Detectives at times. It's worth noting that the past leaves concrete relics behind.