When i first exited the vault, went home and talked with Codsworth, he let me know that it had been 210 years that I had been gone. I did see my spouse murdered and my son taken but I was placed in a cryogenic state again. For all I knew that could have been 100 years ago.
I may have missed something but I did not have any thoughts that he may still be alive. As far as I knew when exiting the vault, everyone was dead. Gone. The world was a different place. My character also assumed Shaun was long gone....