There's ALWAYS 1-2 people that make ANY work environment hell.
But..that's like teaching a toddler what the word HOT means; you simply can't TELL them, they have to experience it. And you get the pleasure of watching them get burned 
My advice would be to encourage her to give plenty of notice and leave on great terms, so that WHEN she realizes how good she had it, that there may be a place for her to return
