What concerns does Jacob have about his parents?

From the text:

Seventy years. By then my parents, and everyone I ever knew or cared about, would be dead, and I’d be long dead to all of them. Of course, provided we survived whatever tribulations we were about to face, I could always go and find my parents in a few decades, once they were born—but what would be the point? They’d be children, and strangers to me.

I wondered when my present-day back-home parents would give up on finding me alive. What story they’d tell themselves to make sense of my disappearance. Had I run away? Gone insane? Thrown myself off a sea cliff? Would they have a funeral for me? Buy me a coffin? Write my name on a gravestone? I’d become a mystery they would never solve. A wound that would never heal.