Which tense when talking about someone who has died?


I'm sorry to ask a question about a sad topic, but which tense do I use when talking about someone who has died.

I ask this because in obituaries,I often see the past and present tense being used. For example : The following sentence is from Elvis Presley's obituary: "Sources close to the Presley routine said he has recently been a heavy cocaine user."
Why is it 'has' and not 'had' as Elvis is already dead?

We also read 'He is survived by his wife and daughter.', but we say "He had 2 brothers."

So, what are the rules please ?

Thank you very much.

Original Post