My urban fantasy setting has, among other things, succubi and incubi. They have all of the traditional traits you'd expect (wings, the ability to change their appearance, superhuman sex appeal bordering on mind control, etc.)
A particular succubus in my story decided she wanted to work as a licensed therapist, but none of those abilities are particularly useful in that department (not to mention that pesky "professional ethics" thing). There is, however, one power available to her kind that might be of value to her and allow her to do her job in ways normal humans could not. Because, like in certain mythos, succubi and incubi also have the power to enter people's dreams.
The things they can do in there are rather complicated, mostly owing to the fact that in my setting, dreams aren't just a series of visual and aural sensations in a person's head. They're whole temporary universes inside a person's soul that the dreamer merely experiences from their one perspective, but which can be observed, experienced and influenced by any supernatural creatures who can enter them.
But of course, the sorts of "therapy" a dreamwalker could do by entering these mental worlds Psychonauts-style and beating the tar out of their clients' inner demons would not have any grounding in reality at all, and any questions I could ask about the value of this ability to a therapist would be downright meaningless, because the answer would be wholly in my, the writer's, control. And besides, physically manifesting within a person's dreams to intervene with their subconscious would be the nuclear option anyway, with great potential danger both to the dreamer and to the dreamwalker. So I'd like to examine the more mundane sorts of options she might have when merely in "observation mode".
Assume we have a succubus working as a therapist for somebody who knows she is a succubus, or at least knows about her dream-walking abilities (so that she can actually convince her client to fall asleep in her presence). Further assume that this succubus is only using her power to observe dreams, and assume that when used in this capacity, dreams work the same way that they do in the real world, and that the succubus can only experience the dreams from the same perspective that the person having the dream experiences them from.
Would this actually have any value to a therapist at all? Do we know enough about the nature and causes of dreams that witnessing a client's dream firsthand would provide any valuable insight to a real-life therapist into how to approach therapy?