What is interesting about this is that they are willing to do it when it seems rather necessary:
My brother and his wife refuse to vaccinate their children—unless they’re forced to, like when their kids were kicked out of school for being unvaccinated, specifically for not having the measles, mumps, and rubella (MMR) jab.
This is not super extreme. Obviously, you maynot agree with him, but... I don't even know where one gets off disowning family.