Probably a pretty good bet that Audrey is psychologically broken. I'm guessing that she is under the care of a private doctor paid for by the Horne family.
What drove her to her state? Brain damage from the explosion? Subconscious knowledge of being violated by Mr. C while in a coma? Maybe she's still in a coma?
Something's definitely going on with her (and Charlie). They managed to be in a different room this time, but this episode's scene was no more revelatory than the one in episode 12 (well, except for how Audrey really seems to be having some mental health issues, not knowing who she is, etc.)
And what did Charlie mean by ending her story?
It does seem like Audrey could still be in a coma and hallucinating / dreaming, or in a psych ward doing the same. It's tough to see another beloved character on the rocks. I expect many mysteries to be unresolved at the end of the season, but I hope we get some clarity on Audrey's situation. And if Richard is her son, hopefully he falls off a cliff.
Charlie's physical appearance may be another clue. Lynch seems fond of using actors with atypical physical qualities (the Giant, Man From Another Place, Mike) to signify an association with the mystical. I'm not suggesting that Audrey is in a Lodge or anything like that, but I don't think Charlie's stature is accidental or incidental.