What a wonderful question!
I believe that the special rules (6th edition lesson manual 11.5) (EBAE XVI.47.f) for the short-form word friend would be used regardless of whether it was a proper name or not.
See also (EBAE XVI.47.b) - The NOTE to this section is on the next page (Page XVI-4)-
EBAE XVI.47.b Note: Short-form words which are common words are not to be considered as proper names when they appear in names of books, articles, chapter headings, publishers' names, etc.
Ex:
Society (of) (Friend)s
MY (FRIEND)LY (EN)EMY.
You can see that the short form for friend was used in both of these examples.
I hope this helps.
--Saralyn