Go punch some pillows and curse. Just get the anger out in healthy ways that will not bring harm to others.
After a few deep breaths, re-evaluate this situation.
A 13 yo girl gets dumped by a 13 yo boy.
They are both young and immature, which is normal.
He is no longer into her - for whatever reason. He tells her it is because she is emotional and intense. STOP THE TRAIN!
An emotionally immature boy just told your SD that he is ending the relationship because she is intense and emotional? Did anyone really expect him to be able to handle, fix or cure her intensity/emotions at the age of 13? I don't want to call this blame shifting - because he really isn't expected to be mature enough to handle a partner that has strong emotions, but the boy did blame her issues for causing the breakup AND SHE ACCEPTED THE BLAME.
She is 13. She is emotional and she may be intense. These are not problems, they are part of who she is while she develops and matures. She does not deserve to think she isn't relationship material because of the immaturity of one lovely, sweet boy.
Please continue to make counseling an option for her. I hope the counselor has addiction experience as well. Just because she was exposed to a toxic parental relationship - does not mean it has to define her future and her entire life. She can overcome and equip herself with the right tools and guidance.
I have a book that helped me understand the dynamics of growing up in an alcoholic environment and how it manifests itself into future relationship of the child into adulthood. The book is "It Will Never Happen to Me, Growing Up with Addiction as Youngsters, Adolescents, Adults"