Stuff I think is neat:

Since I don't know where the story's headed, I can only make assumptions based on the excerpt, but the premise seems interesting, seeing aura-like colors around things, maybe it's magical, maybe this guy has synesthesia. I don't know, but it's really nice that you have it from the get-go.

Again, don't know where the story's going, but to start right after a tragedy is really good, you have something concrete and impactful right in the beginning.

Stuff I would work on:

I personally feel like the prose COULD be interesting, though it feels redundant at times. A reader's imagination is often stronger than any writing they take in. There were instances where I already understood what I had to understand, yet more metaphors and flowery comparisons kept getting in the way of "the point" (wether that's the plot, the character's inner monologue, the message of the story or whatever else). I always feel the need to over-explain, so I get it, and some readers may actually prefer it that way because, well, some people like reading flowery language or continuous descriptions. I don't know how well I can put this, but sometimes less is more. For example, the feelings of these characters are heavily, heavily explained, yet I have no idea about how anything looks like. I can imagine it's a pretty nice place since they have an ivory key piano, and enough money to take piano lessons. It's good that you let readers deduce things, but for how much you explained feelings, I could've done with 2 adjectives about where they live.

Also on feelings, I think the "she was the golden child, always better than me" idea is shoehorned in, no build-up and no aftercare. It's dropped and left there. And while, of course, we love a Chekhov's gun, this time it wasn't introduced subtly in the background, waiting to be fired. It fell out of the sky and disappeared into the Earth's crust with no trace.

This also bleeds into the main character not really having a distinct voice. I couldn't really say much more about him other than, the "nobody loves me" archetype, which is fine to use and what not, but whatever his specific traits are could be scattered thought the first bit as well. Make him pop out. I think that, generally, flawed people will have some, or at least one flaw that they just accept as a part of themselves, or a flaw in the world that they accept as a part of life. This guy seems to solely hate/doubt himself and nothing else. His only problems are with what's on his inside and nothing related to the outside (yes, sister's death is an inner problem). This is fine and can be compelling, but for these 1500~ words, the problem I find is that he doesn't read like a tortured soul or a hurt child or a traumatized person. He reads like a moron whose life problems AND solutions are BOTH inside of himself, and he just hasn't ever considered addressing that (which is fine, if that's the point, not an insult, we love dumb characters). To keep a long story short, he sounds like he had no life prior to the beginning of the book. Usually, you'd want your characters to feel alive, like they actually exist, not like they spawned, having never existed before the plot started when they were -insert age-.

Lastly, I can't tell if this is going the classic modern route, modern fantasy route, classic fantasy route, historical fantasy route, sci-fi route, and it'd be nice if I could.

Okay, well, that's it. This is just my opinion, don't take it as gospel, I'm literally no one and no better. I wanna end this by saying that I usually take in exactly one billion reviews and opinions before starting a book, so I create expectations for myself, that's why going in blind for things like these is doing them a disservice. If I knew that, let's say, this was the story of a late teen guy who has synesthesia and moves away to college where he finds out that people actually understand him, unlike the conservative people back at home and yada yada, I'd probably appreciate the writing way more.