All four children experience varying levels of trauma. There is one specifically who prior to the start of the story had been cast out and emotionally neglected by multiple family members and had to move to stay with different cousins/uncles/aunts every couple of years because they felt she was “unmanageable”. Another grew up homeless without a family.
We never meet their parents, but two of the four children's parents deaths are mentioned (but not described in detail). Of the other two children, one is an orphan (therefore implied parental death) and the other was given up by her family.
There is no eye mutilation, but I thought I'd as a warning: at the beginning of the book Sandry is kept in a very dark room for quite some time and when the doors are opened and a light is shone at her, her eyes hurt very badly. She does recover from this however.
One of the main characters is matter-of-factly described as fat by the author (with no judgement attached to the description, just mentioned the same as she mentions the characters curly red hair). Other background characters do make fat jokes at the characters expense, usually in conjunction with other bullying comments. The bullies are usually shut up in some way or other, although the fat comment specifically is never given much attention after it’s mentioned in any context (like, it never becomes a situation where other characters are reassuring her that “no you’re not fat, you’re beautiful!” or any other such bullshit. It’s just brushed aside mostly.) “Fat” is more often just a casual descriptor of the girl than anything used to target her
It's not a traditional hospital as this is a fantasy world but the children do end up in the sick bay/infirmary, and then later return to their home and remain on bed rest for some time.