Got another one.
This one arrived today: "The following information on the listed individual is required: Great Aunt (GA) who is deceased." GA passed away in 1996, and I sent in a copy of GA's death certificate when I originally submitted the paperwork for survivors' benefits for my aunt who passed away in April 2012 (Aunt P). Apparently there's either a procedure they have to go through or no one bothered to look at the copy of the death certificate.
Back to the form: The information on GA that is requested is for things like address, phone number, etc. which are things I can't provide. I have to admit I toyed with the idea of giving her present address as the cemetery where she's buried, but Mr. Sirius advised against it. (Not that he didn't think it was hilarious, he just thought that it would be counterproductive. He's right.) There's also a section that states, "If you are unable to provide the requested information please write in the space below the name and complete address of someone who is able to supply the information and return this page to us." Really, no one else in the family has more information than I do.
Mr. Sirius suggested that what might happen is that the authority might insist that the survivors' benefits be paid to GA's estate. However, I have a copy of GA's will, and she left her estate to Aunt P. So we're right back where we started from. I told him to keep his ideas to himself, but I'll be very surprised if he isn't right.