Aw this story is just so sad. There's so much in the first chapter and the beginning of the second chapter, building up to show how much Louis loves Cassie, only for you to be kicked in the guts by the end of the chapter after finding out she's dying. I loved the way you described their relationship and how he feels that she's so beautiful and doesn't need make up - I think every girl needs a friend or a boyfriend like that. And the last line about getting his friend back and then losing her in a day was just really upsetting. It makes me wonder how Louis is going to get through this.
Overall there didn't appear to be any grammatical or punctuation errors in the story. It seemed evenly paced and the description was good. The only thing I didn't like was that the text has been aligned to the right side of the page, but that's just my own personal reference.