How do all these styles work together? Well, first off this book is highly insightful and even analytical. The narrator practically plays the role of therapist at times. The narrator often breaks with the plot flow in order to analyze characters. Characters' motives are dissected and we very often get a narrator information dump instead of reading about their actions and dialogue for ourselves. For instance, the last chapter tells us about a number of juicy scandals in a few really brief sentence:
[Maria] hoped to marry [Henry], and they continued together till she was obliged to be convinced that such hope was in vain, and till the disappointment [...] rendered her temper so bad, and her feelings for him so like hatred, as to make them for a while each other's punishment, and then induce a voluntary separation. (48.10)
In the midst of this information dump, where the narrator tells us about things rather than shows us, we get a lot of detailed sentences. Maria has a lot of key words applied to her here, like "hatred," "vain," "punishment," that give us insight into her character's emotional state. And there are lots of other examples of highly-detailed, lengthy sentences in this book, which describe not just the characters but also the world they inhabit, like the scenery. Check out this really rich description of a day in Portsmouth:
The day was uncommonly lovely [...] everything looked so beautiful under the influence of such a sky, the effects of the shadows pursuing each other, on the ships at Spithead and the island beyond, with the every-varying hues of the sea now at high water, dancing in its glee and dashing against the ramparts with so fine a sound, produced altogether such a combination of charms for Fanny [...]. (42.6)
Stylistically, this sentence begins with a description of the scene and moves back to a specific character and her reactions to the day. We often get detailed detours in this book, but they always progress back towards our main characters and the primary plot. But in the midst of all this detail we also have some notable stylistic departures, or differences. We often get a very short, abrupt sentence thrown into the midst of long sentences with lots of dashes and semi-colons. These short sentences really help to emphasize major points. Check out this description of Maria's marriage:
The bride was elegantly dressed – the two bridesmaids were duly inferior – her father gave her away – her mother stood with salts in her hand, expecting to be agitated – her aunt tried to cry [...]. It was done, and they were gone. (21.30-31)
A string of rather choppy descriptions, set off by lots of dashes, are abruptly halted with a very blunt final sentence. Stylistically, these sentences really give us indirect insight into Maria's emotions about her wedding. Instead of telling us that Maria was not happy to be getting married, we get a lot of abrupt sentences that clue us in to her emotional distress.
Hence, we can call the style empathetic at times, since the narrator is channeling the emotions of certain characters on a sentence level. For instance, when Fanny is really upset, her dialogue is often omitted entirely. Instead of dialogue, the narrator gives us a very short description of the types of things Fanny says, which often implies that Fanny is so upset she's not really aware of what she's saying. Or that what Fanny is saying isn't as important as what Fanny is feeling: "Fanny was most civil in her assurances, though she could not make them in a very steady voice" (18.18).
An empathetic style also appears when the narrator is relating a character's inner thoughts and feelings. Sentences that discuss characters feeling are often extremely long and even rambling, using lots of semi-colons. This helps to demonstrate that a character is dealing with a lot of confusing or troubling thoughts and feelings at once. Overall the style helps give us a lot of information about our characters and the plot by using a range of different techniques.