Air,
My dad is a police officer so he's spent many days/nights at a jail. Not once did he get the urge to "off" himself.
Honestly, if a family member of mine ended up in jail, it's obviously because they disobeyed the law and indeed, deserve to be there. Regardless of how many days they are incarcerated..they NEED to serve their time and get on with life.
We are talking about someone with a mental illness. Regardless of medication and therapy, they are still going to be "messed" in the head. How do you deal with someone like that? There's no way you can keep an eye on them 24/7, nor should anyone have to.