Some of the mental illness speculation sounds kinda bullshit. Dissociative identity disorder comes almost exclusively from extreme cases of childhood trauma, often sexual in nature. Anyone who knows her or her situation may wanna check to see if her doctors get kickbacks to prescribe certain meds. It's in their best interest to dx mental illness because insurance almost always covers it.
My guess is, ultimately, she's some cluster B attention whore whose parents were probably more likely to be overly permissive and wishy-washy with boundaries, and she didn't receive much resistance to the things she wanted. Anything less than endless praise is probably painful for her. She's desperate to feel special without having done anything to earn it. Helmet would do well to cut his losses now instead of stick around for some e-girl who will do the same thing to him again as soon as she can.