I was struck by your message, My dad has been mentally ill my whole life. I have been working on getting over that for the last 18 years ,I left home at 17 because I was no longer able to deal with it.And the best thing I ever did was,let him go. Unfortunatly my dad made enablers of all of us.Our lives revolved around his madness.And we didnt count for anything. Only his well being counted.And that we were there to take care of him,sympathise with him,believe his paranoid rages, He threatened many times to kill himself,In his case it was always the unloved child, trying to get our attention by any means possible.I am not saying that you mothers threats are untrue, everybodys situation is differant.In my situation however,it was to control us. We the children became the parent,the caregiver,the nurse,the pychologist.My father is not yet institutionalized, my mom still takes care of him, but we donot speak, I do not visit ect.ect.ect.The way I look at it, he can do whatever he wants to do. I did my time,and I wont be there to hold his hand.He never held mine.
All the Best

This post completely relates to my situation with my mother as well. She has threatened suicide numerous times in the past few years. I have gotten to the point where I do not care anymore. If she thinks her life is so miserable, then she can do whatever she likes with her life. I cannot be controlled by her emotions any longer. I have become her mother, nuturer, therapist, and caregiver. She is unappreciative and lies all the time to her friends and family. It has been a revolving cycle of misery with her. Well, I am done rambling. Thank you for reading.

How'd everything end up? I started this response before realizing your post was from March, so this is too late now really (she's either okay or she's not at this point), but in case you go through similar situations with her again in the future (which you might), I'll say what I was going to say anyway:

The most you could do is call her doctor if she has one and tell them what she tells you, and let them take it from there. It's actually not always even that easy to have someone committed, really. Hospitals don't always have beds, and even if they put you away you might get let back out a few weeks later. But still, if the doctor can get her to admit her suicidal feelings to him then he is required to report it to the police. And at least then she could be protected from herself temporarily. That's really all you can do. I'd say trust your gut in a case like this. If you think she's really in danger, report it. But take care of yourself too. Your mental well-being matters as much as hers does.

Well that"s the whole point isn"t it. I believe in my own situation, I'm done running after my dad and taking care of him, I did my time. In order to stop the cycle you have to break the cycle parent or not. Calling the police and the hospital and or whatnot will change what?
You can"t do both you let go or you don't. And taking care of yourself does not exist with a mentally ill parent,"I'ts all about them, there needs, there wants, how bad they feel ,how sad they feel, how helpless they feel. yada ,yada,yada. And we feel what? Does it really matter? No it doesen't as long as we're there to pick up the mess, were apart of the wallpaper.The ever consistant garbage men,fixers of all,and ever present eggshell walkers. Who's feeling and emotions never matter so why should they now. For **** sake my dad dosen't even know my birthday, when I graduated, what my sons birthday is, cause it never mattered all that matter was him. And how he felt, and that it.so he will end up, how i felt most of my life alone.