My cousin is having delusions. What can I do to ensure her safety?

Highland is a mental health facility. Hospital based labs and bloodwork given at admission and physicals to check for illness so UTI type illnesses ruled out. Referals can be given for psychiatric treatment. They can transfer to state mental health hospital. It’s kind of a dumping ground for different groups of people. Many drug abusers, stop over before some go to prison, low income from the projects. Some families send ripley as a last resort. Many years ago had a good reputation. Not so much now. Mostly younger population.

You have six children and you're not able to look after your cousin.
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?

It does sound to me that this is drug related, and also that you know quite a lot about it. My own nephew had Schizophrenia triggered by cannabis, so I do know that it can happen. Cousin’s mother doesn’t want to be involved, which could be uncaring or could be fully justified – many people on drugs steal from their families and make their lives hell.

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.

Are you saying your cousin has suffered delusions after taking drugs? Then released from treatment?

If she is a danger to herself/others or suffering hallucinations/delusions, call your mental health emergency number for her to be re-evaluated.

Check for a UTI!

What does "given a trip" mean?

How old is she?

What is Highland?