Cunning rule for grandparents:
never but never move "to be nearer the children" because:
1. you will be suckered with grandchild-minding then, just as you become doddery,
2. the children move away from you, leaving you stuck somewhere you did not choose.
Seen it happen time after time.
Our four are 1 hour, 2 hours, 3 hours and 4 hours away respectively. And the nearest is a bit close for comfort.