A sentimental ending to a super-dark novel

For what it's worth at this point, two of the main characters, Patrick and Bridget, take a turn toward the better at the end of volume 3 of the Patrick Melrose novels (intriguingly titled Some Hope). The questions are: Is this enough to redeem them? Enough to lift the series out of its darkness? A credible change? or an author's imposition on his material? Patrick in particular who has made his hatred of his father, quite justified of course, the central element in his life, for some reason toward the end of this society party full of gossip and bitterness and callow behavior, decides maybe he should let it go and feel some "mercy" (a key term in this volume - inspired by a performance Patrick had seen of Measure for Measure) toward his late father and even try to reconcile with his feckless mother. These are fine sentiments I'm sure but they come out of nowhere and do not feel earned, achieved, or sustainable. One would think such realizations would have to come from years of analysis, not from a few moments of sober reflection. Similarly, Bridget, society woman and materialist, learns that her husband is leaving her for a model who (he think) is pregnant with his child (son), snatches up her daughter and returns with her "mum" to her childhood home for some refuge: this, after she had been about as cruel and mean-spirited toward her mother as you can imagine. Now, she's all apologetic. Again, it's hard to believe her sentiments are sincere or that they will be lasting - born out of a crisis and out of a convenience (her mother is a largely unwelcome guest at the glamorous birthday bash). All will depend I guess on how St. Aubyn picks up these themes in volume 4: reconciliation, or reversion to type.