As a parent who has had to seek help from the courts to prevent the other parent preventing medical treatment
I think sometimes it is needed that's what these types of orders are there for to be used when both parents cannot agree.
Children can be like little sponges who will absorb info provided by their parents sometimes that info is biased miss informed and does not take into account the bigger picture.
Whilst logistically its going to be hard to enforce he has just as much right as the mother to make this decision his perception of risk is just as valid as hers as they could not agree its down to the courts to make a decision that mainly takes into account the best interests of the children