riding -
I'm sure you've read about the two Boston Marathon bombing suspects who after committing a heinous cruel act killing and injuring many, were then seen in public places the next day carrying on like nothing had happened. Their 'friends' and families suspected nothing, and even described them as 'nice' people.
Most of us just can't get our heads around how someone could do something like that, and feel nothing about it up to and including acting entirely "normal" before and after such a crime, and while the bombers are an extreme case, the reality is such people exist.
Unfortunately a disordered thinker can often live a full life without most people ever suspecting that what's going on in their head is very different from the rest of us. We people generally assume others think/feel like us, so the notion that we're dealing with someone who acts like us, but thinks/feels radically differently doesn't come naturally. In other words, as frustrating as it is, there is really no way to convince others she has issues. They'll either come to see it for themselves because they are negatively affected, or they just won't.
I do hope for your sake that in the long run you and your kids are able to have a good relationship, though it may be many years before they are old enough to sort out what is what for themselves.