Nigger let me tell you a story.
Raymond Briggs, the author of When the Wind Blows had beforehand written another little graphic novel starring the same elderly couple called Gentleman Jim which was a light hearted story of the old man trying to escape the drudgery of his life as a toilet cleaner by becoming a highwayman.
I read this when I was young and quite liked it, and was happy to find that we had the sequel book, which was called When the Wind Blows and thus I happily started reading it....and halfway through was introduced at the age of 6 to the concept of nuclear holocaust, and how radiation and the breakdown of society slowly and mercilessly kills two terrified old grandparents after putting them through living hell of shitting blood, losing their hair, being eaten by rats, and then dying after deliriously wrapping themselves in impromptu bodybags.
My only comparison would be if there was a Bernstein Bear book that halfway through dumped the bear family in auchwitz and had them each die slowly and agonizingly with every bit of suffering spelled out in colourful pictures