Complex sentence: Fiennes-Tiffin is the son of film directors George Tiffin and Martha Fiennes; the brother of Mercy and Titan Fiennes-Tiffin Bryne, Paul.
Split into simpler sentences: Fiennes-Tiffin is the son of film directors George Tiffin and Martha Fiennes. His brothers are Mercy and Titan Fiennes-Tiffin Bryne, Paul.