How dose max life give liesel purpose? What point dose liesel and max became friends?

Max is a Jew who captivates a young German girl. Although scared of him at first, Liesel finds in Max a kindred spirit. Both form a bond over nightmares. Both lost family members to Nazi ideology. Both gain an adopted family through the Hubermans. Both connect with the guilt of betrayal. Max left his family and Liesel feels she didn't do enough for her brother. Both are brought together through tragedy and both heal each other in the dark and dank basement of the Hubermans.