The e-mails can't be used because anybody could have sent them. She had access to his house and computers.Wrong on both counts.The recordings of his voice cannot be used in court because its illegal to tape someone without their permission.
The maid did not have access to Rush's computer at the time in question, since Rush sent the e-mails when she was not working for him.
Rush's voice recordings are legal, because they are voice messages. Answering machines are legal in Florida.