J'aime bien cet enfant; il dit, du moins, ce qu'il pense. Mais il est d'autres gens qui n'ont point tenu leurs promesses; il est de vieux enfants qui n'ont pas fait leur devoir.
This text is from "Patachou" by Tristan Derém.
*The meaning is as below?
I love this boy. But he speaks what he has in mind. And it is others who have not kept their promises and it is old boys who do not carry out thei duty.
*What is " vieux enfants "? Are they adult men?
I am glad if someone kindly teach me.