Obviously I have no way of knowing what has gone on behind the scenes of that family.
However, I will say that, as wit wrote, 'it (the family court system) doesn't always work the way it should'
Parents can work the system, including just, not doing what the courts order, and it's hard to keep going to court to get the same thing ordered again, with little means of enforcing it. Even harder if you're beaten down from years of abuse yourself.
It's also difficult to provide evidence as abusiveness isn't seen as a transferable thing I.e abuse towards a wife isn't seen as evidence of a risk of abuse to a child, and abuse to one child isn't always seen as therefore extending to all children.
So, just because my stbxh knocked the hell out of me, doesn't mean a court would see him as a risk to his son.
Yet rather ironically, social services made it clear that if be considered complicit in child abuse if i 'allowed' him to hit me when DS was around. Irony being I triggered a SS report by reporting the abuse and asking for help.
When the system works, it's brilliant. But there are flaws.