I need to have a very long and serious talk with her about what could happen to her if they don't wait until he's quite a bit older.
She's a girl, she'll be fine. Lots of women who are actually predatory unlike your girl, rape boys all the time and get away with it because of their gender.
I had this conversation with my eldest a few years ago. Mostly because her tenth grade biology teacher got impregnated by a freshmen and then drove the boy to suicide and fuck all happened to her from the legal end.
And that's in a red state. In prog shit holes it's a million times worse. The cops cover up for pedophilic troons and other alphabet groomers and the Teachers Unions give Carte blanch to female educators to turn their classes into rape camps if they feel so inclined.
There's an enormous amount of female pedos that got completely untouched in their life and destroy hundreds of boys.
If anything your daughter is saving his bacon by sticking with him.