If a misconnect happens, I would be much more comfortable with a friend or family member in the Marriott than marooned in the airport. I really don't think they want people sleeping there overnight, even though they will roll out cots in the event of mass cancellations. And I definitely would not suggest her sleeping outside of security.
For those family members and acquaintances who don't speak English and in some cases don't read the same character set, the Mrs and I have provided a "cheat sheet" for common phrases that they can read in their native language and show someone the English translation of to get some help. For instance, this could be a way to get help her being directed to the first class security line. It's not perfect - people will respond in English - but at least they'll know what she's asking. You could also put some phrases on there such as "I missed my flight and need to be rebooked", etc.
It would also be good if she can have a phone on her where she can call someone who can potentially translate if she gets into a jam or rebooking is not going well.