父は私が大きくなって就職する場合、学校がいかに大切かを話してくれた。

、。

My father told me how important school is when I grow up and get a job.

Literal

Father [topic-は] me [subject-が] big become [then-て] get-a-job [case-場合], school [subject-が] how important [question-か] [object-を] told [for me-てくれた].

大きくなって就職する場合 (when I grow up and get a job) sets a conditional scenario. いかに大切か (how important) is an embedded exclamatory question.