“Sorry it’s not your place”
And if a grandchild were playing with some other potentially lethal item, e.g., a gun, the grandparent should keep quiet because it’s not his place? It’s every adult’s “place” to step in if someone could be hurt of killed.
Unless you plan on trying to take custody it is not your place
Please don’t give me the “it takes a village....”
You’ve raised your children. You had your input.