Even though Leon was a little scared of Meg, he would have showed up with a pack of cards and attempted to teach Kirley some muggle card tricks. After chilling with Kirley for a while he would have declared that he was really looking forward to being a Dad, then had some beer and cake and circulated a bit. He wouldn't have stayed until the end, however, as he didn't tell his girlfriend where he was going and didn't want her to worry.