He isn't, but short of telling her to Google bezness and TLR, there is nothing you can do for her...she will learn the hard way. Even if you tip her off on the scam that's so popular that it warrants it's own name, she will likely throw it back in your face whilst she has her pink specs on.
You've safe guarded the kids, that was the main priority...I think you're an awesome step mummy

My children's father got legal advice on our kids and looked at having a caveat (I learned much new stuff!) put on their passports to stop me taking our boys to Tunisia, whilst so heavily brainwashed and manipulated....he even hid their passports at his parents house

This was never an issue anyway, I absolutely refused point blank to ever risk my children's lives in a country full of jihadists, crime, filth and with shoddy health and education facilities.
They are just not like us, life for a Westerrn child not understanding the culture, religion or language would be so hard.
I've had a lot of shit for refusing to take my kids there, but of all the decisions I made back then....my refusal to place my boys in potential danger is one I've never regretted!
Good for you guys, trust me, even if the shit hits the fan....you've made the right decision