Wonderful story! Your characterizations are so vivid, and the interactions between the boys feel so real, that I can't believe that they really are fictional characters (now, don't gasp, you know its really, really true--say it after me!)
This line just totally destroyed me (in a good way): He raised a hand to Harry’s head and carded his fingers through his hair, and felt a hole in his heart fill when Harry leaned into the gesture.