Who is referred to as an angel in Jerome's Three Men in a Boat and why?

This is a story from a previous river trip, told by the narrator in Chapter XII. The “angel” was a boy who came to their rescue when they needed a place to stay overnight in Datchet. J., George, and Harris arrived in the town late that night, and they searched for an inn. They didn’t like the looks of the first two places they saw, so they kept on walking. When they were told that these were the only places available, they reluctantly turned back. But by then, both inns were filled to overflowing. On the advice of residents, the three men sought out three other possibilities, and each one of them was full of guests as well. The friends were frustrated. Harris even sat down and vowed to go no farther.

“At that moment an angel came by in the disguise of a small boy,” J. said. He took them to the small house that he and his mother shared. They were served a good meal; but the beds were rather small, and they spent an uncomfortable night there. Nevertheless, they had found a place to stay, courtesy of the boy, their “angel.”