What does the The Christmas Pig represent?

The Christmas Pig is a replacement and a representation of boundless love. All throughout the novel, the Christmas Pig hides how much he cares for Jack because he does not want Jack to be upset when DP needs to take the Christmas Pig's body to return to the Up Above. No matter how Jack treats him or what he says about DP, the Christmas Pig is always there for him. He loves Jack unconditionally because his entire mission in life is to make Jack happy again. At first, this can only be done by bringing DP back to the Land of the Living.