My cousin was given a trip and she's not right anymore. She thinks people are after her and everything. Her mom doesn't care, and I found her on the railroad tracks the other day. This has devasted me and I'm terrified she will get hurt. Her excuse was she was looking for gold. Highland let her sign out and I need to secure medical directive responsibility or something, I need to make sure she doesnt leave, I have 6 kids and I'm not able to look after her.
You therefore cannot take responsibility for her wellbeing, so don't attempt it.
In any case, if Highland - which I assume is some kind of rehab - let her sign out, then she is deemed to have mental capacity and therefore you can't have her committed even if you think it would be in her best interests. Neither could her mother, nor anyone else.
How old is your cousin?
You say that you need “to secure medical directive responsibility”. Be very careful about this. Taking responsibility could be just dreadful, as well as not successful, and you already have your hand’s full with your children. Talk to social workers, and consider whether someone else (not you) needs to go for Guardianship.
If she is a danger to herself/others or suffering hallucinations/delusions, call your mental health emergency number for her to be re-evaluated.
How old is she?
What is Highland?