In that one episode he really didn't die he came back in like 3 episodes but if you watch the one about stewie and his future self brain dies from eating chocolate from the garbage (lol btw😂) stewie finds himself from the past going into the future blah blah blah and a bunch of messed up stuff in the episode where brain comes back

when brain dies for good it is in 30 years but that was found out in like season 4 or something like that lol

yha

:3