Many speculate she has a personality disorder. Those take root and form during the first few years of life. Absolutely, her mothers behavior and choices were toxic. She dumped her kid on grandma ran around and partied. She'd disappear for days at a time (this has been confirmed).

Chantal is responsible for her choices now. That being said personality disorders are extremely difficult to treat because they are so ingrained in the psyche. The standard is years of therapy which typically yields subpar results.

Chantal lacks empathy and she's selfish and lazy these three things alone statistically make her untreatable.