After her father passed away, she experienced many hardships.

Literal

Father [subject-が] passed-away [after-てから], she [topic-は] many hardships [object-を] experienced.

亡くなる is the polite/euphemistic verb for 'to die' — more respectful than 死ぬ. ~てから marks the temporal starting point. 困難を経験する is a formal expression.