Yes, you are allowed to bitch her out, and lecture her for months! After my mom's diagnosis she told someone in random conversation that she had been having bad headaches for 3 weeks. I stood there with my mouth open, pissed. Shit I lectured her there. Health problems are not ok.
Also lecture step dad. Seriously, he should have called you when he went to the bathroom or something. Not ok at all.
Oh jeez I'm so sorry. Kidney problems, especially with that background? I'd be flipping my shit too. I hope she recovers quickly and doesn't have any residual renal issues!