I sometimes wonder if the parents can't just put all their energy that they use for fighting each other into just loving the kids.
Loving your child doesn't stop the other parent abusing your child. It seems this mother loves her children very much to keep trying to fight to protect them against what she perceives to be a very serious threat to their health and wellbeing.

Given the potentially serious ramifications/known side effects of immunisation I think she has a some what valid case that this should be perceived as a serious medical procedure that can't just be decided upon by one parent.