It's not actually a patch. The "mapping.xml" file is a file the developer made to name the characters. Someone edited it, so it would say "mother", instead of "landlady", for instance. But you can edit this file, yourself, with a notepad programme. If you play the game in your own native language, other than English, you can also translate the namings in that file.
But to answer your question, the MC calls Claire "Mom" or "mother", if you use the "patched" "mapping.xml" file. If you edit the file, yourself, you can have the MC call her whatever you want.