The young man's response is an immediate wince. Followed, of course, by a nod. "...People don't...remember this place, if, or when they leave. I know Mr. Joestar at least had technically died just before arriving, so I at least hope wherever he went it's at least somewhere but..."

But if Joseph's grandmother said nothing, it's not her fault. That, at least, is the point.

He wonders to himself, what else he can say though. What else he can do, really. What he can...

".........you know, technically you're a grandparent yourself."

Nailed it.