How does dolphus Raymond explain dills crying ?

Dolphus says that Dill doesn't understand the harsh realities of the world yet: he is still too innocent,

He jerked his head at Dill: “Things haven’t caught up with that one’s instinct yet. Let him get a little older and he won’t get sick and cry. Maybe things’ll strike him as being—not quite right, say, but he won’t cry, not when he gets a few years on him.”