Henry addresses Catherine in Ch. 24 on her idea the imprisonment or murder of a wife is the only crime a bad man can be charged with.
I am sure Henry is aware such things can occur in England. The laws in 1800 did give the husband something close to absolute power over wives anddaughters. That is a reality of patriarchy.

Henry dismantles Catherine's wild supposition about his father.
Afterall, he was with his mother so bears witness to Catherine her death was naturual.
This is quite a slippery passage of NA. I think Henry's chief concern here to shake Catherine out of her gothic illusions.
This is my take; He cannot give Catherine assurances of any benevolent charecter of his father.
So Austen gives Henry the insistance on authority, law and social constraints rather than an appeal to Catherine of his father's nature.

Henry is unable to disguise Eleanor's unhappiness with her father. And General Tilney does unleash his power quite brutally upon Catherine herself.

My view is NA is also a 'coming of age' novel. It operates as a parody but we shouldn't ignore the real danger Catherine experienced, already discussed on this thread.
The General obliges his guest to make her way home alone in a public coach, short of money without even a travel companion. In the C19th, English roads were very dangerous. A single woman alone risked her reputation. She doen't know the route. Catherine is completely alone and must rely on her commonsense.
It is a bad experience , nearly as bad as an incident in a novel. There is no excuse for the General to treat her like this.

Yet it reveals Catherine truly learns to excercise commonsense attitudes in the real world. She 'reads' the situation well and returns home safely. She is cured of imposing illusions on the real world.

My view is the first part of NA forms a Defence of the novel with a joshing of some readers, publishers and Compliers, clarified in Ch 5. There is some parody of readers-- Isabella Thorpe personifies a parody of a reader attempting to emulate a heroine so ends up making herself ridiculous.
The focus of the second part of the novel is a parody on readers who impose illusions on reality.
Overall, I think NA can be viewed as a bildunsregan (sp ?) of 'coming of age.'

C.L Johnson makes an interesting comment,

'It has seemed to many readers than Austen's parody in Northanger Abbey debunks gothic conventions out of an allegiance to the commonsense world of the ordinary, where life is sane and dependable, if not always pleasant. But by showing that the gothic is in factthe inside out of the ordinary, that the abbey does indeed present a disconcerting double image,..., Northanger Abbey does not refute, but rather clarifies and reclaims, gothic conventions in distinctly political ways.
Austen's parody here, as in the juevenilia, "makes strange" a fictional style in order btter to determine what it really accomplishes, and in the process it does not ridicule gothic novels nearly so much as their readers.'

C.L Johnson, 'Jane Austen. Women, Politics and the Novel', p.34

Perhaps NA is a complex admission of the gothic.