Notice I tacked on a weasel phrase "in most contexts." I don't think there is a consensus about falsifiability, and I wasn't the one who brought it up. The person who did seemed to understand it backwards. Since Aristotle and Newton operated without the concept, I'm willing to shelve it.

Grandma going to heaven can be reduced to absurdity, and isn't very important, except as a typical line of bull.

It is falsifiable if you can find a single non falsifiable thing that would be useful / treated as true.

"Life has meaning."

Actually, this doesn't fit here, because "useful" implies "for a goal", and if there's no ultimate goal to life, then nothing is useful. So "life has meaning" is just another example of something that is only useful if true. Ah, well.

"Grandma went to heaven" is a statement of fact about a very specific matter that is either true or false.

The person uttering it has not seen, heard, smelled, or touched a single piece of evidence to verify this supposed fact.

Indeed, they're saying it either because they're sincerely repeating a myth they've heard since they were credulous children, because they want to mollify a grieving child's anguish, or both.

If you make a claim about the physical location of a human being, yet you have absolutely no evidence to bolster your claim, then you're making a claim that is not falsifiable and should be considered false.