It feels, all at once, as though Regulus has been holding his breath since he first saw the other man on the beach - and as though, finally, he can let it go. He wouldn't relax just at the comment about Sirius, even though it means he can let go of the fear that this is James, even though it means that Harry knows who he is and hasn't immediately jumped on the defensive. That alone wouldn't be enough.

It's the last part that makes all the tension momentarily drop out of him, makes him break into one of the rare smiles that actually reaches his eyes. He looks, as it happens, a lot more like Sirius when he smiles.

"He's all right?" He almost laughs, his relief is so great. "Merlin, I've been worried since I got here. Draco said something about it, but..." But vague comments about what might have been going on in Draco's time haven't set his mind at ease nearly as much as this. Maybe it's because there's a ring of truth in how Harry talks about it, an honesty that doesn't make Regulus think that he's saying it just for the sake of politeness.