With a dream so abstract, I'm not sure what to say or think about it
The narrative establishes a connection between Sasha and the boy, perhaps a person from his past or an embodiment of a section of his subconscious that he cast aside to cope with something. That last one is a bit of a stretch, but I'm just trying to make sense of everything. Not that it's a bad thing that something doesn't immediately make sense. That's why so many shows are popular long after they've aired, because we don't know what the hell we saw but it confused us and made us feel things.
Hmm, was Sasha embarrassed he took a joke so seriously or was he having lewd thoughts about scoring some young, shota booty? Maybe he was thinking "hmmm...he's cute enough" or something
I just thought that part was humorous. I would've put more detail in the feeling of getting his throat slit. Of course that's hard to do since you most likely have no idea what it's like to get your throat slit and I'm pretty sure sensations like that are dulled in dreams, but I do know that getting cut with a knife in any capacity burns like hell. Describe the feeling of being enveloped in confused terror as he exsanguinated (fancy word for bleeding profusely) through his neck, and then waking up perfectly fine.
Noticing the word count, I'd say you shouldn't worry about it. See, I doubt my story is going to end up being novel length and I'm not going to try to force it to be that way. Write as you feel the urge to, so you ensure that you only produce good content. As you get more absorbed in your own world, the pace will naturally pick up. At least for me it does.
Anyway, good job on Part 5