The common convention is to refer to almost anything about someone who is dead in the past tense. "He was married to ..." "He was a great artist ..." "He had a degree from such-and-such college", etc.
Depending on your religious beliefs, you may believe that his spirit or soul still lives, and thus there might be things you would say about him in the present tense.
For example, I understand that Mormons believe that marriage is eternal, that you will still be married to the same person in Heaven. Thus I would not be surprised if a Mormon said of a dead person, "He IS married to ..."
The only exception to this that I can think of is records. Like we will say, "Fred Smith holds the record for most home runs in a season" even after Mr Smith is dead. But even other things that don't really expire, and that we say in present tense when a person is alive, become past tense when he dies. Like, "Fred Smith IS a graduate of Foobar College" for as long as he lives, but when he dies it becomes "Fred smith WAS a graduate of Foobar College".