Parents just want what they think is best for their kids... even if it's a delusion or simply misguided.
If you don't plan on faking it until you're independent:
-Tell her, if she's right, you'll get to see your grandpa and be with him...it's important to be with family, even after death. Grandpa shouldn't be left alone for eternity.
-if she's wrong, then nothing happens... and she'll be the one responsible for the splitting of the family.It's important to be with family, specially while alive.
If you don't plan on faking it until you're independent:
-Tell her, if she's right, you'll get to see your grandpa and be with him...it's important to be with family, even after death. Grandpa shouldn't be left alone for eternity.
-if she's wrong, then nothing happens... and she'll be the one responsible for the splitting of the family.It's important to be with family, specially while alive.