I know it's hard. I didn't do any of it without crying and worrying.
My son ran off once and threatened to run in front of the train a few blocks away. Another time he overdosed on medication and was hiding from the police. I had to tell the police to back away so he would come out. I waited until he passed out and called them back and had him 5150'd.
He overdosed on one of my medications once and shaved half his head and was delirious. I 5150'd him again.
I could go on and on. I was also all alone without family support.
We don't have what they need even when they seem to want help.
We can't do it. They need their own treatment and support. Detoxing is just the first step in that process.
If your grandson ends up in the ER again you could let the staff know that your grandson gets suicidal during detox and has behavior that may need psychiatric help and then go home. Just start by making your home a place of safety for you.