Should go without saying, but props to everybody for not trolling this.
But like ol' girl said, there might be some serious grudge shyt going on that you don't know about. She probably got touched before, dude. That's purely speculative, but I've seen that situation play out between fam so many times. Daughter gets touched, mom didn't do enough to or wasn't able to stop it. The daughter grows up and acts out with a dude who ain't shyt and always has this underlying beef with the mom.
I say all that to say definitely be with your moms and console her, that should be the first priority. But this seems like a deep wound that they're gonna have to open up and move past for them to ever truly get right within. Whether that means them coming to terms or getting somebody to talk to openly about it, it'll probably be necessary for the healing process. For your mom to even consider taking her life means this is bigger than some blow ups and the daughter being cruel, this is triggering some shyt that shakes her to her core, that she's gotta get right with in order to heal. Hopefully ya'll can be strong for her and can kinda take shifts looking after her, because she's going to need it as she picks herself up and rebuilds.