I went into this with high hopes. Apocalyptic novels are a guilty pleasure of mine, after all. This... was disappointing to put it mild. Reasons structured below cause there are so freaking many (spoilers ahead duh)
Bleak Worldbuilding
The book is set after an unnamed apocalyptic event that remains undefined from start to finish. Not a disqualifying point in itself but it gives a first hint on how the author operates. After said event, the whole world basically died: nature is dead, the air is toxic with ash, the sun can't penetrate the ash clouds and gray fog, resources are diminishing, so people are even turning to cannibalism to survive. One would think you could get a compelling story out of that setting, right?
Nope. The setting adds absolutely nothing to the story except to “explain” why every character except the main ones, a father and his son, turned into cannibals (and rapists and slave keepers cause for the author that's apparently the same pipeline). Every time the setting is mentioned is repetitive, even when the “plot” moves to a new place. The story wouldn't been different if it played out in a tesco parking lot or the Appalachian mountains, that's how little the surroundings matter to what the characters are doing (which isn't a lot in the first place).
Annoying Main Character
When I tell you, I wanted that man to die more than any character I ever read about, just so I would no longer be subjected to his inner monologue. He's a misogynistic, hardcore christian, paranoid, abusive coward that somehow manages to make me root for actual cannibals who eat their newly born. Yes, that's a thing that unironically happens. His son has the personality and defiance of a cardboard box, and Dad still manages to find offense and give him shit for existing while the literal world is ending.
There's also no character development. You meet the characters at the start and that's who they are, cause why change a definitely-not-winning team? Can't have the reader actually developing sympathy for your characters, that would be outlandish.
I also have to mention that all tension and any pity you might have felt for their situation evaporates halfway through the book: The main conflict of the book is the struggle for resources and the main character's fear that they might turn into cannibals, too. Then they stumble upon the solution: A forgotten bunker, filled with supplies that would last years, safely hidden away in a somewhat intact orchard. And then they leave! I may have thrown the book when I got to that part. Dad also never gives a reason for why they leave, just that they have to leave so they can reach the ocean, not to do anything there or something, no, just to get there to maybe find safety... So not a brain cell to be found and no character credibility either.
The Worldview The Book Portrays
I'm all for separating the author from the art, unless it's such an obvious self insert as it's here.
The author wrote this book after divorcing from his wife and fighting over custody of his son. So, of course, the wife in the book is a selfish, dumb and hysterical monster for holding the same opinion that Dad does (aka that dying is better than being raped or eaten by the “bad people”). But because she killed herself and also wanted to kill the son, she is the bad guy here but also the ideal the man still longs for. The only other female characters you see in this are a woman eating her baby after giving birth and a few women held as sex slaves/food and paraded around in chains and collars naked. On the risk of psychoanalyzing too much into this, I think there's a connection here, to that divorce situation.
Then there's the whole savior complex the Dad has. Christianity is never explicitly mentioned, but the author is apparently very religious, and it shows in his writing in a way that happens when authors don't have enough skill to actually build a character instead of just projecting all their beliefs onto it without any reflection whatsoever. But it becomes pretty clear that the only reason why the father and son are the only “good” people left (despite them abandoning, stealing and killing just like the rest) is their faith. Portraying non-christians as automatic pedophilic rapists who eat everyone, even kids, and don't value human life or have any morals just rubbed me the wrong way, especially since this is a regularly enforced thing every couple pages.
All of this combined with the poor composition (you could shuffle the scenes, it would make no difference), poor writing quality (most meaningless dialogue you ever read) and complete avoidance of any punctuation (have fun reading every paragraph twice to figure out whether it's something a character is saying or not) just makes a nightmare of a book. I feel entitled to be reimbursed for the time I wasted, but sadly that's not a thing, so I hope you don't make the same mistake.