Poor Gavroche.
And Gavroche was Eponine's brother. When she was dying, they could hear him singing nearby and she told Marius not to tell him know what happened because he would be angry with her.
He was living in the elephant (I had completely forgotten about the elephant!) and he was watching two little boys that were actually his brothers, althought none of them knew it. The Thernardiers had sold the boys out to someone, but the older boy lost the address (if I remember it right, the paper with the address blew out of his hand and he couldn't find it again) and they didn't know where they were supposed to go, so they were lost in the streets.
Gavroche had gotten them food (again, it's been years since I read the book, so I may not be getting this entirely right), and the little one was crying, so when Gavroche gave him some bread, he told him, "Here, poke that in your gun."
Later, at the very moment Gavroche died, the book caught up with the two little boys again, who were still living in the streets. The older boy had taken some bread out of a fountain (where it had been left for the ducks), gave it to his little brother, and said "Here, poke that in your gun."
It was like Gavroche's spirit had moved into this other boy, and he wasn't entirely gone.