The hand coming down on his head does cause a tiny flinch-- but only because he wasn't expecting it.

In any case, Envy doesn't have to worry about that, because immediately following it is a small clatter as Wrath drops his spoon and twists around to lean heavily against the other Homunculus. It's barely a conscious thought process-- although his arms following along and wrapping around Envy is.

If he hadn't cried himself parched already, the tears would have started flowing again at the 'b' word. But for now, he just crushes his face against Envy's chest. Which will probably get the point across enough.

He missed his big, really stupid brother a whole lot.