English Translation
He turned out her father.
The given translation should be “He turned out to be her father.” Otherwise it sounds like he is throwing someone’s father out of the house. 
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Agreed. They don’t match. FYI: the sentence source Tatoeba has already fixed the mismatch.
ID: 471120 - He turned out to be her father. = ID: 100864 - 彼は彼女の父親であることがわかりました。
By the way, ID: 100864 in Japanese still sounds unnatural a little to my native ears. It should be
彼女の父親は彼だと判明しました。(pron. はんめいしました)
I intentionally swapped the subject and the complement because starting from “he” is unusual.
彼は彼女の父親であることがわかった means “Tom could be Mary’s father or Jane’s father. And then, it turned out that Tom is Mary’s father.” The only case I can come up with is “the hospital accidentally mixed two new babies and Tom raised someone’s daughter without knowing the accident.”
彼女の父親は彼であることがわかりました means “Mary didn’t know her father. Her father could be Tom or Jack. And then, it turned out that it’s Tom.” This is more natural context.
Also, 〜であることがわかりました is understandable but sounds wordy. 〜がわかりました is okay but inserting であること in this sentence structure makes the whole sentence awkward. 判明する is frequently used in this context and sounds much more natural.