It's always been my contention that when an actor dies in the real world, it doesn't mean that all of the characters they played in "present day" Toobworld should also be considered as having died.
Jim Hutton died back in the mid-1970s, but I think his portrayal of Ellery Queen lives on.... although he's now probably about 102 years old!
But when that fictional character is the tele-version of the person playing him - that is, a celebrity portraying him(or her)self, then we have no choice but to consider them dead in Toobworld as well.
(One extenuating circumstance - if the episode in which they appear was set in the future. As such, even if author William Gibson gets killed by a bus tomorrow, in Toobworld he'll be alive at least until 2012 - the year during which 'Wild Palms' takes place. And the tele-version of Frank Gorshin lived at least a few days longer than the original model did here in the real world, thanks to an appearance on 'CSI'.)
This was brought home with true finality in the February 14th episode of 'Gilmore Girls'. Betty Friedan had only passed away ten days earlier, but her death was remaked upon in that episode.