I'm from the Review Tag :)
Hello, this is an interesting start to your story. The pace was good overall and you kept Draco in character, so I applaud you for that. However, there are quite a few basic things that can be improved upon in order to make this story even better.
First off, is there any other way you can think of for Malfoy to find himself in St. Mungo's, to meet this witch? I was immediately turned off a bit when I started reading this, because Malfoy's mother being sick and/or dying is a bit cliched. I've begun to get the impression that in the fan fiction world Narcissa is a very sickly woman, just because it happens SO often in fics. I'm sure there are other possibilities you could use, unless her sickness is essential to the later plotline!
Also, you need to be very careful with description. It's good for a writer to find the right balance for description in their writing. Always remember this: show, don't tell. Don't say what your character is doing, but rather show what they're doing through description. This can be anything, from using their 5 senses (touch, taste, sight, hearing, smell) or describing their feelings and their body's reactions to certain things (Ex: goosebumps, shivers, butterflies). But at the same time you have to make sure you don't go overboard. Description is wonderful, but limited description is better!
Make sure you watch out for run-on sentences. If you have an especially long sentence that is becoming overrun with commas and the like, trying splitting the clauses into separate, smaller sentences. This will make the writing much more easy to read and appear less cluttered to the writer. Commas are vital to dialogue as well, as it helps add to the natural cadence of speech. Try saying the lines you're writing out loud. If you pause between a word, insert a comma there (Ex: "Fine suit yourself" -> "Fine, suit yourself"). Also make sure your dialogue sounds natural. I noticed in some spots, the words sounded stiff and unrealistic. You seem to omit contractions a lot in your dialogue, and although this is good for something like a research paper, it sounds unnatural when it's supposed to be coming out of a person's mouth.
In the beginning, I noticed this: 'He cared for his mother and they had grown closer since the end of the war, but he hadn't felt this remorseful since Crabbe died in the Room of Requirement five years ago.'
It seems like you're trying to convey that these are Draco's thoughts. However, if these were his thoughts, wouldn't they be in the first person and thinking of what is going on, rather than describing the way he is feeling. Direct thoughts from a character should be written as if they were speaking these words. This is more like a narrative. A better way of saying this could be: 'I can't believe this is happening. What if she dies? What if she's in pain?' This shows the pain he's going through and how it's affecting him. The bit about Crabbe could be included in a narrative directly afterwards, separate from the thoughts. This is just a suggestion, though.
It took a little while for the actual plot line of this story to take effect and get into motion. I'd suggest maybe cutting out the bit between Malfoy receiving the news about his mother and actually going to the hospital, or at least shortening it considerably. You don't need to describe every little thing a character does. This can become tedious and repetitive, and will be a turn off for a reader, as they might get bored. Maybe focus more on the hospital and what's happening later? I'd suggest doing that anyways, since I found the chapter end rather confusing. It was hard to follow what was going. Maybe add more dialogue?
I found it interesting that he'd been so remorseful over Crabbe's death--is this a new side of Malfoy we're seeing? If so, I hope you expand on this more. In the books Malfoy is always portrayed as being removed from those his age, with little to no emotional attachment to Crabbe or Goyle. I'd love to see something other than this typical approach, because I've always had the opinion that there's much more below the surface when it comes to Malfoy!
Overall, I think this story has a lot of potential. I'm interested in seeing where it goes. Please don't take my CC above personally, I happen to be very picky when it comes to writing, and I tend to be a thorough reviewer! Keep writing! :)