Armand is in some ways the least suited of all to be a father. He doesn't even have a last name to give them. And yet, this novel turns him into a father against his will. He goes from being a street urchin to being a caretaker of children. He doesn't even like children, and yet, fate brings them together around Christmas time. When he brings them to see Santa, that adds an element of magic and mystery, because now the reader knows to expect perhaps a Christmas miracle.
Interestingly, the theme of fatherhood is mentioned even here, because the novel is set in France and in France, they don't call him "Santa Claus," they call him Father Christmas. The element of fatherhood is also present in the children's wish. They ask Father Christmas for a home, which is exactly what a father might provide, except that Armand doesn't even have a house for himself. He lives under the bridge where the children have recently ingratiated themselves.
Armand's story takes him through a long cycle of homelessness, rejection from his own bridge, rejection by a woman, and then after he secures a miraculous job opening, he is accepted by the woman (having also saved the day a few times now), restored not to the bridge but to a new home, and given a role to play in his community. He even has a new last name. Interestingly, the Christmas miracle doesn't just fix his problems; it allows him a method by which to bless other people in need.