That's a really bizarre and oddly Platonist take on things. Your grandfather was viewing laws of nature as rules imposed onto reality by some outside force, and which therefore need some "mechanism" to be in place to "enforce" them.

But I think a more reasonable understanding of natural laws is that they're our attempt to describe the cause-and-effect patterns observable within reality itself. They're not being enforced, they're simply manifest.

Construing "nothing can exist" as a rule that has to be enforced, and not just the absence of any patterns of causality that would produce something that exists, seems to be an error. It actually seems to be a more sophisticated version of reifying the concept of "nothing" such that "nothing exists" would be interpreted as describing the positive existence of an entity called "nothing" rather than merely describing the absence of any such entities within the context.