Children whose rights have been violated can submit complaints directly to the UN Committee on the Rights of the Child, if they have not received help in their home country.
This has become possible thanks to OP3, a relatively new protocol to the UN Convention on the Rights of the Child. Children in countries that have approved the protocol therefore have better chances of making their voices heard regarding their rights. Sweden has not yet approved the protocol. You and your friends can contact your politicians and demand that they do so.