Sirius had woken after the initial knock on the door. Even with as deeply as he'd been sleeping, a lifetime of caution had triggered his instincts to wake up. Lily had gone to answer the door, and so Sirius had curled up again beside James, who still hadn't left his side. The voices in the other room seemed calm enough, and so he was just starting to let his eyes close again when the footsteps brought someone to the door.
Sirius sat up, blinking for a moment, and staring at the man who dropped down beside him. James was beside him, and this young man had green eyes.
"Harry," he breathed, reaching for the boy who was no longer a boy, but a man, ready to fall straight off the bed if that's what he had to do to hug his godson.