Growth
Frank together with the other kids is too young by the time their parents leave them at the hospital. They still depended heavily on their parents for everything. In this environment, these children are molded into young adults by the individual experiences they acquire. By the time their parents come back for them, they are responsible young adults who thrive in the ecosystem built inside the hospital and also the world.
Isolation
When most of the children arrive at the hospital, they are forced to cut ties with the outside world. Children who still depend on their parents are forced into independence. For a child, this is very troubling and unsettling as it disrupts their routine. To reset to a new normal, these kids begin by isolating themselves and eventually opening up to new people in the same situation. They get used to being alone that they find peace and tranquility in isolation.
Survival
Frank and his family fled from Hungary, surviving the First World War. They have endured the Holocaust and now a polio outbreak is upon them. Frank is also learning to walk again at the hospital. The children at the hospital are kept there to protect others from infection. While there, they find innovative ways to interact and make worthy friendships and relationships as they wait for their departure from the hospital. In the novel, despite the situation, they always manage to pull through and survive.
