I just went through that with our (new) first grandchild. Fortunately our daughter and son-in-law agree about vaccines and my daughter is watching like a hawk to make sure nobody tries to sneak anything in during any pediatrician appointments.

We were lucky - we got an early granddaughter. I'm not sure my older daughter will even be able to when she wants a kid. She is a teacher and no matter what we told her she hasn't met a booster she doesn't like. She left our house a conservative, went to school and managed to make it out at least as a moderate, but now all her friends are lefties. I'm still trying to get her back to being conservative again but it is hard to do when she lives across the country from me. Time will tell.