It took me a while to reflect upon the stars I should give to this book - four or five - four point five would be neat but here not possible option... The book totally shattered me in a way it made me cry and ponder too much over many observations, but I was at the beginning really puzzled by the grammar and scant use of complex sentences.
After a while I got used to it and realised the purpose of such writing style - it perfectly matched the down-hearted state of protagonists' minds. The Earth in which they live dies, slowly but consistenly and inevitably, and in such world without hope and future, where everything material if not edible is completely worthless and pointless, the remarks and thoughts are scarce and restricted to the current state of awareness, basically to their survival insticts and values as human beings at the brink of extinction, which they in this story really are.
The father sees the only fire worth living for in his own boy - that boy is his light, his hope and his purpose... The cause of the apocalypse is in this story irrelevant - it might be super-volcano, an extra-large comet, a nuclear catastrophe, whatever - that would be interesting question for a debate though, as such scary scenario might really happen, not in the near future, I hope. The real essence of the story lies in what makes our life valuable, worth living for, when we are left without absolutely anything but our own kin and the values we honour from our ancestors and the close loved ones... Shall we descend to the lowest levels of savagery or retain some dignity, honour, selflessness and love in the life that offers nothing but despair.