In Texas she could still file charges. But you would probably need to file the charges in the state where the molestation occurred. If the molestation occurred in California, then you really need to check with the Sheriff's office or Prosecutor in the county where the molestation occurred to see if they will prosecute your father and/or if the statute of limitations has run.
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Your post indicates wrongful acts in two places [CA &TX]. Your sister should contac authorities in both. Though there are some hurdles to actual prosecution, your sister can still report it. I cannot advise or suggest as to TX law wher I think a second and later event took place.
She should also speak to a local PI attorney.
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