The law is that she can't give consent but he can.
So she hasn't done anything wrong cos he consented.
It's because it's dead easy to get a 7 year old to agree to have sex with you. Just go 'do you want to do soemthing fun? How about we have sex? Want to do that?"
And they don't know what they're agreeing to. So the law is that under 16s olds can't give consent, they aren't smart ernough to know what it means. So he's had sex without his partner's consent, legally.
She hasn't.
The law is an ass. It's the same legally when the bloke is 15 and 11 months and the girl is 16 and a day.