This gets asked a lot.
Volo was in magical stasis, as were (by blueflame item means) individuals like Mirt.
Many mages have means of prolonging lifespan that don’t involve lichdom, e.g. potions of longevity (and they didn’t always work the way they do in 5e).#Realmslore
— Ed Greenwood (@TheEdVerse) May 26, 2021