I've heard MANY bad (gymnastics are only gymnastics if they're controlled, otherwise it's anywhere from strained contortion to outright caterwauling), but none worse. That was truly godawful, even by amateur standards.
Honestly, I thought that maybe this was a singer who really couldn't sing but had been studio massaged into sounding "good" on record. Milly Vanilly.
But instead she was drunk. Tore down. Still don't know how well she really sings, but for sure, good luck on the rehab, and also take a long hard look at your management. That was a very...unhealthy experience.