My father seemed disappointed that I didn't pass the exam.

Literal

Me [subject-が] exam [to-に] passed-not [because-ので], father [topic-は] disappointed being [appeared-ようだった].

落胆しているようだった — seemed to be disappointed. ~ようだった expresses appearance/inference. 受からなかった (didn't pass) is the negative of 受かる.