“There is no “right” to kill your kids.”
They are not killing her. The girl has a condition that will kill her. They’ve put it in God’s hands. Sounds like you would prefer to hand it over to the government.
Absolutely nothing I've said could lead someone to that conclusion.
It is up to the parents if they want to stand aside and watch their child die. The state cannot compel them to keep her alive.
If anotehr person sees a fellow human being dying and tries to help her, the state cannot compel that person not to help.
It is the parents who are trying to use the power of the state to compel other people to act against their own moral judgment.
I am not advocating using the state as a weapon against the parents.