Meet my Hatchet of Death (or, some other colorful description RC Lewis and I come up with at any given moment). This is how I edit myself, it is how I edit others. If you think you want to play with me and my hatchet, shoot us an email.
We all know the first line of a query is your "hook." I call the last line the "sinker." You want it to punch them in the face, in a nice, friendly kind of way that makes them unable to forget you after having read the 300 other queries in their inbox.
If you're looking for query advice, but are slightly intimidated by my claws, blade, or just my rolling googly-eyes, check out the query critique boards over at AgentQueryConnect. This is where I got my start, with advice from people smarter than me. Don't be afraid to ask for help with the most critical first step of your writing journey - the query. My comments appear in green.
Being told he is going to die is an unacceptable diagnosis for Alex. After all, he is not even shaving yet, and he is already having to decide who should have his things when he is gone. Decent hook, but it could be punchier. Rearrange some of these thoughts and use word economy to give it more zip. Ex: Learning that he's going to die before he needs to shave is unacceptable to Alex. -- There's everything in the able lines (minus giving your stuff away, which isn't necessary to the query, I don't think). Word economy is your friend in queries.
But there is another option besides death.
Alex enters a life pod to preserve his body until a cure can be found for his illness, but he remains in the cylinder far longer than he ever expected. When he is revived by the binder Nezbit, Alex discovers that he is in a world that bears little resemblance to the one he left. Technology has disappeared, extinct animals have reappeared, and humans are no longer the only people. Interesting... but if technology has disappeared how would his life pod be sustainable? There may be a good answer for this (green tech?) but it raises the question. Also, I don't know what a binder is? That might need explaining. If it's a genre thing (like most agents who rep the genre would know) then you might be okay, but I would still recommend some illumination on that.
Once he accepts the unsettling notion that he is not dreaming and that these people seriously believe him to be the fulfillment of a prophecy, Alex decides that dying while trying to stop the imminent invasion by the disturbingly-named Monster King (and his army) beats just sitting around and dying anyway. So... he's still sick, right? Also, this is a single sentence. A bit longish. Also, the tone here is very light, with an edge of humor. If this is the voice of the book, that's fine. If it's not, don't got for being flippant.
With the help of Nezbit and a dozen “specialists” from around the kingdom, he begins a mission to slip through the enemy army, avoid the living dead, and slay a creature best described as an armored rhino standing on his back legs. What could possibly go wrong? So, what's a "specialist?" Is there a reason it's in quotes? Again, this voice is light and we're talking about heavy stuff. Like I said, if this is the voice of the book, that's fine. If not, it won't do you any favors in the query. "What could possibly go wrong?" is a generic way to end the query, so definitely come up with something better.
Overall, this is pretty generic. It's the future, the MC is a "Chosen One" type character, there are good guys and bad guys. What makes this different from every other story with that same base? The illness could be a differentiating factor, but we need to know more about it. Is he still sick? Does he need to save his people before he dies from it? What's a binder? Are these the other "people" you reference in the opening? Right now this is raising more questions than answers, so get some details into it.