"Our child's mental illness"

We as parents rang the Police to help get our child to emergency hospital in Bunbury recently as our child was mentally unstable threatening to kill them-self and other mental issues. After a few hours and after our child was assessed by a  psych nurse they decided to send our child home. But also the phych nurse spoke to us as parents for some background on our child's illness and told us our child would be seated in the waiting room and they will get back to us. Then about 1 hour after that, we got a call from our child to say - ha ha I'm home they let me home.

It was so disappointing that we had to hear from our child that they were sent home, while we were waiting to hear from the phych nurse. Makes us feel that we go there for help and in our opinion, it gets thrown in our faces. Hopefully our child doesn't kill them-self, but we don't know what else to do.