Does anyone know a good website to find out about a persons death for free?

Unless you put it in your question, we can't tell what country you are in. It is the most frustrating thing Y!A does. Even if you go in through Y!A Australia, Y!A Canada or ordinary Y!A, all the questions in English go into one big "pot". I'm in California, for instance. http://www.tedpack.org/obit.html will tell you how to find an obituary in the USA. That will tell you when he died. They usually omit the "How". You can sometimes guess, if donations are to be made to the Cancer Fund, Kidney Fund, Diabetes foundation . . . His death certificate will have cause of death. They are almost never on-line. You'll have to buy a copy from the county clerk.