I can't tell if she's dead. As funny as it would be to just kill off the main antagonist in such a throwaway moment, I don't know if this series would actually do that.
She LONG stopped being the Big Bad of the Story by this point. Cancer Wife took the reigns, it's the classic "Bigger Bad USURPING the Big Bad Wannabe" since it was because of HER in the first place all this started, without it, SHE would never have been able to START her plan of turning MC mom into a Goddess. Not that I feel for HER as she essentially HURT MC, his father AND his mother in her MAD Yandere Selfish wish to make MC's mom something she made PLAIN CLEAR EVEN IN THEIR YOUTH SHE NEVER WANTED! It's WHY she hated MC! She thought his mom was meant for GREATNESS and if she never met his father and had him, she wouldn't be held back. She was NOT but a Selfish Yandere (as they are, what do you call PUSHING affection on someone who DIDN'T WANT IT but Selfish!) and she DID try to kill MC TWICE (First time was what lead to his mom's coma and abduction as she attempted to attack MC as a child when she couldn't take that his mother's choice "didn't fit her world view" and the second was when he handed him to the Crazy needle lady as a expandable experiment, she didn't care that he was buried in a unmarked grave when they faked he died, just HAPPY he was dead. Note her shock of him still being alive as remember she HATED him and made it clear once he remembered WHO she was and what happened that day when he was a kid as she traumatized him by both attacking him, hurting his mom and then taking her away as he could only helplessly chase after her futilely. And honestly it HAD to happen. Cancer Wife never really HID that she was shady and sketch at best. Of COURSE she was going to be the Final Big Bad (with Mom likely being the FINAL Threat, I'm sure she'll be defeated by REMEMBERING who she IS Since Crazy endgoal was to make her FORGET the life and everyone in it to BE THE GODDESS SHE SAW HER AS! As she saw MC and his father as HOLDING HER BACK. When Flashback and her words BEFORE she threw a tantrum and tried to attack MC made it clear she NEVER liked her "old life" the expectations, ANY of that. While she was KIND to Crazy, it was clear she NEVER expected to see ANYONE from that life again, and likely hoped she'd LEAVE with NO incident which sadly happened in the WORST way when she attacked MC as she did! That's why she had that breakdown, the school and her parents were TRYING to force her to become a SUPER HUMAN and she broke, and their response was to ABANDON her, Crazy is the product of that OBSESSION MC Mom NEVER wanted, asked for or EVER to be involved with again! You can compare her to CLAUDIA from Silent Hill 3 who was SO broken by the cult she OBSESSIVELY believed her ONLY friend Alyssia WANTED to birth god, and refused to hear HER, her reincarnation Heather OR ANYONE to the contrary, even KILLING HERSELF trying to birth god if you go for the GOOD ending because Heather gets it OUT OF HER and Claudia dies OBSESSIVELY trying to "birth it herself" after stuffing the fetish in her mouth.
I do agree and expect her not to be dead. She still has to pay for the crimes she did to MC and his parents forcing her INSANE world views on them (and trying to kill MC, and brainwash his mother after keeping her comatose and SEPERATED from her family for MUCH of her son's childhood while victimizing them with the whole "Wife's with super-powered clothes" thing! Note she's been in the apartment the WHOLE FUCKING TIME since the kidnapping, so next to doing her plans, she was OBSERVING them as they were the Managers of the Apartment complex, and having them DEAL with her "Creations" who never hesitated to HARM and/or MOLEST them! I really don't want to see her get a Karma Houdini, at best I hope she's left wheelchair bound at least! Getting off scot free is annoying for the shit she pulled!