I am so sorry, but each time it gets harder the closer we come to letting go.
It's good to have a list of places that can give him real help, I used to give my son a meeting list, a list of detoxes (there were 4 in Toronto at the time), and the Salvation Army number (they offer free rehab and a very good program).
I don't blame you for snooping, I was Queen Detective in my day, but I soon realized than I "knew" and didn't need proof of anything.
I can't tell you what to do, you know the drill and you know what it right for you.
But I will offer prayers up for your son...and for you too. Being the mother of an addict is not for weenies.
Hugs