I mean, he died in COD1.
he came back in COD2. Alive, somehow. Even though he died.
And then he comes back in COD4, at the age of like 130.
And somehow lives at COD6.
I blame all the people who cried when he died originally in COD1, I was one of them, but I was too young to go to the COD forum and complain about till infinity ward brought him back. Thank god for that.