GK,
I am way late to this party, sorry to hear of your family's trials - both you and your son.
"At least in jail I know he is alive."
Very true. There are several members of my Nar-Anon home group that have said that they previously thought that having the child in jail would be the worst thing they could think of short of death. Then their child ended up in jail mostly for theft or possession - while they were in jail they relaxed - their child was being fed on a regular schedule, had a roof over their head, had medical care if needed. and there was a reasonable chance that they were not using (sadly not 100 percent on this one!)
Although your immediate need has ceased, the alarm system that folks were groping to remember is "Simply Safe". Easy, do it yourself installation, affordable monitoring with no long term contract, cell phone connection to police / fire, comes pre-programmed to your specifications.
Stay strong and don't forget to breathe.....
Keep coming back,
Jim