When I look back at this passage, it's still one of the most harrowing I've ever read. I've read a lot of books, but this one about child neglect and abuse, which is so extreme as to leave a child locked in a cupboard with a baby to both starve, which results in a small boy holding his dead sister, is just shocking. It's shocking because it involves children and because it happens. Fantasy horrors etc never strike so much as they simply aren't real.
I think as adults, it hits us more too. We abhor the idea of this happening to a child or an adult doing this to a child. And it is a loss of innocence for our children when they read it and discover something dark about the world.
But at the same time it is written for children of around 10. And children take different things from it than adults do and they understand it on a level that is right for them too. My 8 year old reading it understood what had happened when we read it and talked about it. She agreed it was a horrible and wrong thing to happen...but I do t think it played any more on her mind then as a horrible thing that shouldn't happen, anymore than her brother stealing her sweets or other minor horrible things she could think of. And it's not quite spelled out in the passage what has happened, so children need to draw on what they already do know and understand, or what a teacher or parent might help them towards seeing to understand it at a different levels.
The world is full of horrors and one of parent and teachers roles is to show children, appropriately about these. I do think fiction is a good way to deal with many issues and it is right that children start to learn about the real world. Through fiction my DC have learned about prostituion, female genital mutilation, abuse, the holocaust, racism, genocide, bullying, depression, domestic violence.....Their lives and minds aren't darkened and spoiled by knowing about these things, but they are gradually growing up and able to think about and talk about the ideas in light of the story and the real world. Upper Primary onwards is a journey to adulthood and there's lots to learn and find out about.