Link nods. Still little, then. But old enough to play the ocarina.

And if Link was the more talkative sort, he might make a remark of how Harlock must miss her. But he's not, and Link doesn't consider that the sort of thing worth saying; of course Harlock misses her.

So instead, Link just stays quiet. He's comfortable letting the conversation lapse into silence. Or maybe more ocarina playing, if Harlock is so inclined.