Unbelievable. If nothing else this story illustrates perfectly why home educating parents should not be paranoid and defensive about the authorities wanting to carry out checks on the progress and wellbeing of their children, and they should embrace transparency and be co-operative for the sake of children like this one.
While I am sure it's only a tiny minority there are undoubtedly people who choose to HE as a way of isolating their children from the rest of the world in order that their own very disturbing regimes can be imposed and systematic abuse can go undetected.
I have read similar things before and it always comes back to 'no-one knew anything untoward was happening because the family were socially isolated and the kids were HE'ed so no-one else got close.'