However, sentenced or not, he more than likely caused post-traumatic stress, which often results in abnormal behavior and thoughts of Self Delete. He did not kill her, however he enabled her to kill herself. It's the butterfly effect, basically. Would she have killed herself if he hadn't done those things? Could she cope in a situation similar had it not been her father? Had someone been there for her, could they have helped prevent it?
Many factors go into such occurrences, and while she made the choice to kill herself, and she went through with it, one should not chastise her now deceased mind for being "idiotic". Committing Self Delete is a stupid, stupid choice, but that does not make the one who considers and or does it moronic.
And the "mentally strong", define that please. Even those whom cannot support themselves "properly" may provide something into this world. A life is a life.