I know that since the father of the Dukes of Madrid and San Jamie, the Count of Montizon, lived appart from his family in London Duke Franz V of Modena, Archduke of Austria-Este was kind of a father figure to his nephews in Modena. When Franz V died the title "Archduke of Austria-Este" and some estates went to Archduke Franz Ferdinand and other estates went to Maria Theresia (later Queen of Bavaria). So upon the death of Franz V did Carlos and Alfonso Carlos recieve anything (estates?, money?) from their uncle?
-Duke of NJ