So why the title stepmother? It is because you become a 'surrogate' [that's not the right word, can't think at mo] mother once you take on a family.
She KNEW he had kids, she must make him think that the situaton is in some way OK, as he is happy to leave the kids there. Either that or he is such a poor excuse of a man & father, she should never have had 2 children with him.
There is more to this, I think. 3 parents would not let 2 young children, 1 with special needs, be treated like this.
I said before that as a mother, I couldn't let my children be in an enviroment like this, but also as a mother, I couldn't actively neglect 2 other children either.
These children have no one on their side, they have no voice & how do we know that they aren't completely unhappy with their situation? Moved from pillar to post, but no one actually seeming to care?
How long would it take the parents [here I mean all 3] to realise if one of them were missing? It's a sad fact that they have no one looking out for them.