It wouldn't surprise me if there was a "You could have died!" moment or something like that where death is mentioned, but I doubt the show will ever have anything outside of vaguely implied, but never acknowledged, deaths, like AJ's parents.
If they did, they'd win a hell of a lot of maturity points...if there's such a thing.
Tealove is best pony.
Pony Fanon Workshop
Sesame Street addressed death in one episode. Poor, poor Mr. Looper!
The end of the world as we know it. Like weekends usually are, but more dire.
Pinkie as an alicorn
.... this is the way the world ends...
I believe in Christianity as I believe that the sun has risen, not only because I see it, but because by it I see everything else.
C. S. Lewis

And Twilight's only companion will be Spike who will grow to be a handsome adult dragon. However, dragon lifespans pale in comparison to alicorns, and he to will eventually die before Twilight.
There are three constants in the universe: creation, destruction, and Fate. Guess which one am I? - Id the Imp
@ Ud The belief around here is that dragons live much longer than ponies.