This picture (somebody else posted upthread) of him with his hand round her neck tells us everything we need to know. Even though it looks like a “jokey” and posey picture, you can see the controlling element is there. It isn’t normal for a person to put their hands round their partners neck like that.
Splitting up, slating them on social media, then getting back together MULTIPLE times in such a short space of time is toxic. He’s obviously controlling and abusive. She has absolutely no self worth or self esteem. She’ll believe every one of his apologies and “I’m sorry, I love you”.
Those bruises are not hickeys. They were not done via a fight with a girl. They were done by him. She isn’t going to admit that. But for her safety and for the safety and well-being of her children I hope she leaves him and seeks help.