what makes Liesel's adjustment to life with the Hubermanns particularly difficult? how does papa help her?

Liesel has had a difficult time. She has watched her brother die and she knows she might never see her mother again. Liesel has nightmares. Hans plays the accordion to make her feel better.

She has nightmares about her brothers death while she’s trying to go to sleep and her foster dad helps by coming in and singing to her .