With slow, diligent movements you rub the shampoo into Derpy's mane, gently massaging her scalp with your fingers. She's mostly calmed down now, only sniffling a little from time to time as she sits in the bathtub, facing away from you.
You're not sure whether she would be able to take a bath by herself considering the state you found her in and even though you'd like to ask her about it you don't know if you should. She must have been through a lot if a light scolding is all it takes to make her break down in tears and maybe you should give her a little more time to calm down. You feel like right now she can definitely use the attention you're giving her anyways.
On the other hand, maybe the best course of action is to actually go a step further and to actively talk to her, to let her know she's not alone. You feel a little dizzy as you stare at the back of Derpy's head, unsure of what to do.
Ultimately you end up doing nothing, just washing Derpy's mane and coat in silence until there's a sudden shift in her body:
"Anon", she asks as she turns around to face you, "what's a human?"
Right, you did use that word earlier, didn't you?
"You see ... I'm a human", you begin, though when you realize how unhelpful that explanation is you continue, "Biologically speaking humans are kind of similar to monkeys."
"But you don't look like a monkey at all", Derpy objects with a confused expression on her face.
"Well, where I come from there are quite a lot of people who said the same thing", you say, slightly bemused.
"Where did you come from?", Derpy asks, now turning around fully to face you.
"Twilight said I come from a completely different world, one who's space and time are entirely disjoint from what we're experiencing right now", you explain, though it only earns you a confused look from Derpy.
Right, she probably didn't understand a word of what you just said.
"I come from a faraway place", you say, trying to put things into words she'll understand, "And I've lived there my whole life until suddenly-"
You clap your hands for dramatic effect, making Derpy jump a little in surprise.
"I wake up here in Ponyville and I don't know how I got here or how to get back. Do you understand now?"
"Yes", Derpy says as she seems to look off to the side, nodding absentmindedly.
Suddenly she jerks her head back at you and despite her misaligned eyes you feel like Derpy's gaze is becoming very focused.
"Have you seen my mommy?", she asks, sounding strangely hopeful.
"No", you answer, feeling like that is not what Derpy wanted to hear from you, "I don't think so."
"Oh, okay", Derpy says, clearly disappointed by your answer.
"Why ... why did you ask whether I've seen your mommy?" you ask carefully.
"Because you said that you come from a faraway place", Derpy answers as if that explained things. Apparently sensing your confusion she adds: "Mommy and I went to the hospital. And normally when we go to the hospital I'm hurt but that time I wasn't hurt and I thought that maybe I got hurt and I didn't notice and that made me feel a little scared. And then mommy and I went to a stallion with white clothes and a weird tube hanging around his neck and he said something to mommy that I didn't understand and then mommy started crying."
You don't like where this is going.
"And then mommy said that we'd have to stay in the hospital for a few days and I said that I wanted to go home but mommy said that we couldn't. And then mommy got really sad and she told me that I'd have to be strong now and that she'd go to a faraway place. And then I told her that I wanted to come with her but mommy said that I can't and that made me feel really sad. Mommy said that I'll see her again when my time has come and that I'll have to be patient."
A small tear mixes in with the water on Derpy's face as she squeezes her eyes shut.
"I don't understand. Why did she have to go? Every day I think about her and I want to see her again and it makes me hurt inside."
Shit, what are you supposed to do now?
"You said that you came from a faraway place, so did you see mommy?", Derpy asks you again.
"I'm sorry", you say even though you'd like to tell her otherwise, "But I think your mommy and I have been talking about two very different kinds of faraway places."
"But what kind of place did mommy go to?", Derpy asks, clearly upset, "Mr. Hoofington said that she's now in the ground but I know that that's a lie. Mommy once told me that sometimes ponies say something that's not true and that that's called lying and I know that it's a lie because the ground is not far away. It's just her body that was put into the ground."
Actually even in Equestria where souls are a reality it is not clear what will happen to you once you die. The boundaries between dimensions allow passage only in one direction, hence you will never be able to return home, and ponies will never know what awaits them in the afterlife until after they're dead.
Derpy looks at you intensely, as if expecting a word of wisdom that you do not have.
"I'm sorry, Derpy", you say as you look away to the side, "I just don't know about these things."
You're not looking at Derpy directly anymore, but you can see a tremble running through her body, accompanied by a quiet sob.
Though your words were honest, you're beginning to regret them.
Why did she have to put you on the spot like that?
Hundreds of brilliant unicorns weren't able to figure this stuff out, how are you of all people supposed to know?
When Derpy's body is shook by another sob you quickly look back at her, and she stares right back at you.
"Look", you improvise, "I know that sometimes life is hard and it can hurt."
You pause for a moment to think of what to say next.
"But at the end of every tunnel there is a light and no matter how bad things may look right now in the end everything will turn out fine."
You feel like your words are neither original nor particularly meaningful, but Derpy seems to completely absorb every syllable you speak.
"Because when you're doing good things to others, good things will be done to you."
"Really?", Derpy asks wide-eyed.
If someone had just told you the same thing in all seriousness your response would have been a laugh at most.
"Of course", you say with a smile and somehow despite everything Derpy looks like you managed to make her feel at least a little bit better.