Sounds really awful, and worryingly unsafe.
How close by do they live, slim?
I agree about talking to the school - if the statutory services can't intervene on your say-so, then the school might alert them.
It's difficult. It would be hard to prove actual neglect, even with all the details in your post, but it's very poor parenting 
BBC have reported the following about Reform!
What can I give my granddaughter who’s off to uni


