My system has decided on suicide as an acceptable way to move forward if our life gets bad enough (which is likely but hasn't happened yet - March at the earliest.) we have an alter who wants to die much sooner & impulsively, instead of following our plans and timeline. We rely a lot on written communication. She has different handwriting which I recognize and sometimes she signs her typed messages.
She feels pain intensely and feels the need to escape it. We try to prevent her from getting triggered, so we cut off the worst sources of stress, emotional and physical. I no longer talk to my family or get too close to my parents' neighborhood. I have a restricted diet because I have gastroparesis and a lot of foods cause problems for me. It took a lot of work (journaling and therapy) for us to understand the external sources of pain and connect them to how we all feel.
We acknowledge her pain and remind her that we DO have a plan to end our life. We set up barriers to prevent impulsively doing so. Our chosen method is incomplete, we have the hard to obtain part but to be successful it requires driving to a store to buy something, so I have to be sober & since we only have one car, I can't go buy that thing when my gf isn't home. We let her cry and scream when we're home alone. We use drugs for multiple reasons, preventing her from attempting is one of them. We finally got medical marijuana and edibles this week; I'm hoping that helps so I don't have to do harder drugs as often.
I don't know how to make her feel better but I am trying to prevent her from feeling like the rest of our life will be miserable, by avoiding pain when it's in my control and assuring her we have a peaceful way out to use before we end up homeless.