I'm going to tell my friend that if she didn't vaccinate her (hypothetical) kids then they couldn't be around my (also hypothetical) kids
Why wouldn't you want her kids around yours?
I don't want my kids to be sick and suffer from disease
You are right to protect your kids from harm. It's unfortunate that your friend does not share your belief, but family comes first.
I can't believe she wouldn't protect them.
I am glad you are looking out for your future children. You should also know if they are vaccinated they should be unable to catch an infectious disease, that's how they work.