Silvio's seen some shit, man.

You know, for all the characters I have with "dad energy" but no kids, I basically always imagined that Silvio does have children—and they likely have children too. He doesn't get to see his kids very much, and I wouldn't discount the possibility that they're "not on speaking terms". From Silvio's perspective it's a sacrifice he's willing to make because he needs to keep his family safe from THEM anyway.

But even without the aliens he's been around long enough and had enough terrestrial adventures that he surely has plenty of stories to keep his grandkids entertained. Maybe one day, after peace between our worlds has been established, he can tell them everything.

A bonus artistic freedom piece by  Horned_Hut