Thanks!
Lore-wise, Father is Ava's father (who would've guessed?) who created the Dreamscape so she had somewhere for her to go when stressed or anxious. However, now she's stuck there (not that she's complaining) and has forgotten most elements of the real world. Some characters are real (Kenzie is Ava's gf, Kate is a neighbour who Ava gets along with, etc) and some aren't.
Her father can see into the Dreamscape, but isn't fully capable of controlling it. All he can really do is ask for Ava to wake up.