"Ask a Librarian" --- http://www.broward.org/libraryhttp://www.broward.org/library You could request lookup of old city directories, if there are any volumes as early as the 1930s.(I recall seeing 1942 city directories.)When your ancestor is omitted from city directories, you will have a clue as to date of death.
The Librarian may be able to direct you to archives of Employees of Ft Lauderdale Prison Records, if there were any.
If you have reason to believe that your ancestor died in Florida, you could request a death certificate --- information is on this web site: http://www.rootsweb.com/~flbrowar/howto.htmlhttp://www.rootsweb.com/~flbrowar/howto.html
You should mention in your request the date of birth, and that your ancestor was still living in 1930.