‘That Quidditch Cup’ll have our name on it this year,’ said Wood happily as they trudged back up to the castle. ‘I wouldn’t be surprised if you turn out better than Charlie Weasley, and he could have played for England if he hadn’t gone off chasing dragons.’
Sorcerers Stone, chapter 10
Can you imagine Charlie reading in one of his letters from home that Ginny has been practicing quidditch plays nearly every day? How, the moment she’s done with her lessons, Ginny is out the door and borrowing his brothers’ the old brooms in the shed? Not only that, but she’s good. Shockingly good for her age.
So Charlie starts writing her. Letters telling Ginny about the dragons in Romania and occasionally dropping hits in how to balance better or pull out of a risky dive. When his parents and Ginny come to visit him that Christmas he gives her his old copy of Quidditch Through The Ages for her gift. Molly scrunches her nose as Ginny reads hungrily, asking him about with the notes and doodles he’d scribbled into the margins from his time as the Gryffindor seeker and the team captain. And when they get home Ginny practices even harder, until the blisters on her hands turn to calluses
Then years later when she earns a spot on the Gryffindor team as chaser Charlie demands a play-by-play of every game. Between her, Ron, and the twins he jokes with the other wizards and witches at the dragon sanctuary that he almost has a full quidditch team.
When the war is over Charlie gets an excited letter from Harry explaining that the Holyhead Harpies are trying to recruit her. Halfway through the letter he whoops with joy and announces to anyone that will listen that Ginny will be the next Gwenog Jones. Whenever the Harpies have a game Charlie checks and double checks that a wizard wireless nearby to hear the game.
Not even the dragons are enough to shut him up when his baby sister is mentioned scoring a goal (although several disgruntled dragons try).
Charlie and Ginny talking quidditch whenever there’s a family meal and he’s in attendance, even after she retires as a professional athlete. Because Charlie’s joy and excitement in regards to Ginny’s success as a quidditch player is second only to Harry.