Perhaps in your example, the grandfather is the catalyst, not KEK.
Romans 10:
14 How then will they call on Him in whom they have not believed? How will they believe in Him whom they have not heard? And how will they hear without a preacher? 15 How will they preach unless they are sent? Just as it is written, “How beautiful are the feet of those who bring good news of good things!”
Whatever fertilizes the seed...
I just think there is gonna be a lot of fertile ground for believers to work with in the months to come. One needs only to be still and let the Spirit give you the words.