@mrmm
Boy, where is he in this timeline? must be 45+ years old already
Well, lemme explain it this way. Suppose that the current you have a car. And the future you came and took the car to his timeline. Wouldn't that mean your car is now missing until the year future you took it?
So in this case, he went missing since 1988 until the present time where he emerge.
If the older him exist too, that mean it's a different universe and time.
There are many time travel theories.
The common one is when you change history, it effect the future as well.
The other one is when you change the history, your present time still the same. Example you save Titanic from sinking, but when you go back to your time, your history still state that Titanic sank after striking iceberg. That mean the one you save is Titanic from a different universe.
There's more theories, but I forgot/dunno what they are and how they work.