I’m a grandparent to two awesome kids, 8 and 6, we keep to their home routine, with a little leeway. Bedtime and mealtimes are the same. We purchase the foods they like. My grandson thinks grandmas rules are bigger than mommies. We get our grands for 3 separate weeks in the summer. PA days, March break, overnights It is a huge disservice to your grandchildren to not keep consistent rules.