Sorry to hear that - if you cannot use the method for verifying by ID, then you might want to try reporting the profile as underage (even if it is fake)
As the parent of child in the profile content, you (hopefully) should be able to get it removed.
https://www.facebook.com/help/contact/?id=210036389087590
If you're reporting a child's account registered under a false date of
birth, and the child’s age is reasonably verifiable as under 13, we
will promptly delete the account. You will not receive confirmation of
this action, but you should no longer be able to view this child’s
timeline on the site.
If the reported child’s age is not reasonably verifiable as under 13,
then we may not be able to take action on the account. In this case,
if you are not the parent of this child, then we strongly recommend
that you encourage a parent to contact us personally, using this form.