Ok, but how cute would it be if Remus and Sirius raised Harry, and then one day Harry brings home Draco as 'a friend' and they can both tell Draco's not only a friend, but they wait to mention anything because Harry will tell them when he's ready. Then, about the eighth time he's brought Draco around they hold hands underneath the table, and Sirius "accidentally" bumps into them while he was bringing in the green beans for dinner just to see their reaction.

Harry finally tells them by asking them what the best place for a date was (their immediate reply was 'astronomy tower'). It takes them a bit to get used to Draco, but by Harry's 6th year they're the main Drarry shippers