How do I get Followers of the Apocalypse? Dogmeat will remember the Vault Dweller from Fallout and join the PC. He can be recruited by the Chosen One, by simply showing their Vault 13 jumpsuit (in other words, undress) and speaking to the dog.
Fallout 3 expansion set Broken Steel optionally (enabled by choosing the ‘perk’ bonus “Puppies!” after reaching 22nd experience level) allows a killed Dogmeat to be replaced by a new one (with twice as many hit points, that is a starting value of 1,000 instead of 500) whenever he dies during the game.