Oh, I'm not saying he was alive when Familicide hit. Just saying that he was already dead from misadventure/accident and the Clan couldn't Rez him for one reason or another. (Although---this might be a little convoluted---was he paranoid enough to kill himself before the natural end of his life, with instructions or a pre-loaded rune to Rez him if the leader of the Clan felt a threat was coming that they couldn't handle or hide from? Sort of a "In Case of Emergency, Break Glass and Rez Epic Illusionist"? It's not like the Clan was going to generate someone with his kind of power on their own, given the absolute rarity of Epic NPCs.)
Then Familicide kills everyone w/o warning, and no Rez. Until a blundering, panicking V knocks on the wrong piece of wood...
Edit: All of this assumes---and I'm probably wrong---that a character's natural lifespan doesn't proceed while they are dead. (Jeez, that looks weird, re-reading it.) IOW, if you were going to live 85 years normally, but die 45 years in, can you be Rezzed 80 years later (assume True Rez, Wish, whatever) and keep going for 40 more years?
Good pickup on the quarter-Draconic instead of half. I didn't catch that initially, and it doesn't give him enough natural lifespan. Probably.