Animals being in captivity is bad for their instincts. In captivity, animals lose their more wild side that's in touch with their original and natural environment. Unless an animal (specifically whales in this case) is injured and cannot be in the wild, they should not be kept in captivity.
sentence 4 is most clearly contains foreshadowing
The impact that the Nigerian Civil War has had on Jonathan's point of view is that he feels lucky if his family is alive and has access to the basic necessities of life.
