Throwaway account for obvious reasons. Apologies if this is not the right subreddit for this kind of thing, please point me in the right direction as I wasn't sure where to post.

I'm a 47 year old single father of two, both my daughters (17 and 23) live with me. Yesterday I got a brief but very strange phone call from my ex-wife (divorced almost 10 years) whom I rarely talk to (maybe 1-2 times a year and only in matters pertaining to the kids). She "just wanted to find out if I am okay" (totally unusual but I shrugged it off). Today, my ex-wife, wakes me up by blowing up all our phones. When I answer she is wailing and sobbing and screaming and demands to know if our kids are alive and well. I awaken them (they were sleeping) to find out, and of course they are okay, but she has since hung up. Then she calls back a little later and says she is 10 minutes away and will be at my house shortly to talk with all of us (she lives 30 miles away).

When she arrives she is sobbing and asks me "how much I know". She begins telling me that she has been hearing voices in her head for at least 6 weeks. She says these voices are "clear as a bell", that she has heard them outside the home but they seem strongly amplified at her home (she lives with her long time boyfriend), especially coming from the vents. She says the voices tell her "terrible" things about herself and about me and our older daughter. She told me that the voices told her that our younger daughter was dead. She said she believe she is surrounded by witches and that she believe that her two neighbors in her townhome complex are somehow "in on it". She demanded of my daughter to know whether or not she had "cast a spell" on her. She was surprised that I wasn't already aware of any of the things she described. The whole time she is sobbing and clearly upset.

I assured her no one had cast any spell on her and I asked her whether she had been taking any drugs lately. She said that she had, although she refused to say what kind. She stated she last used 2 weeks ago. She (apparently earlier) confessed to my older daughter that she has used heroin last month at some point. I know for a fact she has done cocaine in the past, and signs suggest that her current boyfriend and her are apparently into other drugs as well (not sure what kind though... my daughter had discovered a glass pipe - not a weed pipe - once upon a time at her house). She is also known to be the victim of recurring physical abuse from her current boyfriend. She herself has a history of unstable and violent behavior in the past, part of the reason why I divorced her in the first place.

My gut tells me that her instability, combined with abuse and drug use has led to some kind of psychotic break, either that or she was acutely intoxicated today when she came over. According to my daughter, the ex-wife said later that she had been awake all night and "hadn't slept in days".

Obviously her behavior deeply disturbed all of us, especially our daughters, and they were able to persuade her to get into the car so that they could seek help. At the ER, the ex-wife relayed the stories about the voices to the physicians and counselors. They took her blood pressure and said that it was extremely high. She explained that she was just upset, but the person taking the reading said that they have only ever seen such a reading due to drug use. Ultimately though, she refused any treatment, refused to pee in a cup or have blood drawn or anything else. She ultimately demanded to be discharged, and not having a clear reason to believe she was a harm to herself or others, she was released.

Personally, I'd be fine never dealing with her again, but she is always going to be the mother of our children, and that is who I truly am concerned about. My older daughter has seen enough past nonsense with her mom that she feels like cutting ties and finding ways to cope herself, but my younger daughter is very sad about it and wants to help her mom. At the same time, I don't feel it is healthy that my daughters (especially the younger one, who is dealing with her own, unrelated issues) to have to put up with this erratic behavior from their mom.

What can my daughter do, if anything, to help her mom that won't be too emotionally taxing for her own self? We've seen that driving her to the ER doesn't help. I've suggested she could try to make phone calls and set up appointments with counselors, etc., but ultimately her mom is going to have to be the one to actually go to the appointment and I don't feel like my daughter should pay the emotional price of dealing with it.

What can I do, to prevent another such occurrence? Honestly who knows, one day she could hear voices telling her to do things, maybe bad things... it does make me concerned about security. I can't just have her dropping by on a moments notice to have a meltdown. It is upsetting (and possibly dangerous) to the kids as well as myself.

What could be the cause of the ex-wife's behavior? I'm no doctor, but my guess is mental illness combined with drug use (maybe some kind of amphetamine?) and physical abuse has just driven her over the edge. I'm mainly just concerned about protecting the physical and mental well being of my daughters and my self, and of course my daughters are concerned about their mom's mental health.

What are we in for? Hopefully she can get help but I feel it is likely that she will not, and that I will have to expect random things like this affecting us in the future. What can/should we do?

TL;DR: Me (M47) living with my two daughters (17, 23) woke this morning to my ex-wife (divorced 10 years back) whom I rarely speak with coming over to my house randomly to have a possibly drug induced psychiatric meltdown