Why are some chapters in bold and some in regular font? What is the purpose of this in relation to the narrative?

Why is Amabelle reticent to reply to Sebastien when he asks about her father in Chapter 7?

Amabelle says, “There are times when I want to be a girl again, to touch this doll, because when I touch it, I feel nearer to my mother than when her flesh is stroking mine” (57). Why might touching the doll make her feel a more intimate connection to her mother than touching her mother would?