DM, I am so sorry that you find yourself here. I feel your pain.
I have two homeless or semi homeless right now. My son C, turning 33 this month, and my daughter S, now 28. It’s been a long road with both of them.
S very much fits your daughter’s profile. When she was tested in elementary school, her IQ was tested at 81. Cut off for services based in intellectual disability alone was 77. I was told without a formal learning disability diagnosis or a ‘discrepancy’ between expected and actual performance of standardized tests, she did not qualify for an IEP - essentially, her low scores were ‘as expected’, with no discrepancy, so no services. (I understand they’ve since dropped the discrepancy method for the newer RTI, or response to intervention, method, which she probably would have qualified under. Water under the bridge, I guess.) in high school, further testing put her at an 85. Like yours, she went through multiple emergency holds in her teenage years (for self-harm) and one short term residential stay. Waiting times for adolescent psychiatrists were at 6-9 months and they did little for her when they saw her. We tried various medications, which she would not comply with. She has since been diagnosed Borderline (BPD), Obsessive Compulsive Disorder (OCD), and Generalized Anxiety Disorder (GAD). I suspect fetal alcohol syndrome based on what I know of bio mom, but that has never been diagnosed. She is volatile, non treatment compliant, and extremely stubborn.
I was never able to get her on any services either. She always seemed to fall through the cracks - as you say, not low enough to qualify on intellectual disability alone, and the other diagnoses didn’t seem to qualify her for anything. I didn’t know much about it all, and the whole rest of my life was falling apart during her young adult years, so I didn’t push any further. I wish now I had.
I have learned that she is capable of more than you might guess based on her tested IQ alone. She is capable of holding down a service industry job, paying rent, etc. she has developed a lot of street smarts. I take the IQ test with a grain of salt anyway - it’s not a flawless instrument, and doesn’t take into account the ability of people to grow with experience and environment. People do grow. Our daughters may never be Rhode’s scholars, but they are capable of learning and growing. I really believe what matters most is not what you start with but what you do with it.
In contrast, C has a very high tested IQ, around 130, and is still homeless. He dropped out of high school st 17 so he could stay home and read Hegel and Chomsky. Passed the GED with no study and scored in 99th percentile. But on paper, he’s just another high school dropout with a GED and spotty employment history, and barely employable. And he has no common sense or life skills. In some ways, S has the advantage in that area.
If I had to do it over again, I would have pushed harder for services when S was your daughter’s age. She is out of control now, unwilling to go in for any testing or help. She mainly lives off of men - she is tiny and vulnerable looking and very pretty and knows how to use that to her advantage. She couch surfs when long term arrangements fall apart. Like yours, she is too volatile to do well with regular roommates, and doesn’t earn enough to afford a place on her own. She is an alcoholic and a drug addict, mainly pills and cocaine I think. It breaks my heart. I don’t know how to help her, or even if I can. Like you, I have limited financial resources and can’t subsidize my kids long term without jeopardizing my own security and retirement.
Others here have had more success and experience in getting their kids on services and I’m sure some will chime in soon. I think if I were you I would keep looking in that direction. It may take some time, but this is a long road we are on.
Beyond that, remember that she is an adult, low IQ or not, and is making her own choices. She is not so impaired that she can’t be held responsible for those choices. And she may be capable of more than you think.