While it is easy to judge, I do not think those of us here are doing so, in the main.
Nobody here is in the position to judge. We might, but if we do, we are mainly trying to shore up ourselves, because we know in our hearts how much we blew it, or fear we did.
My son had a brain injury in 2010 and he has chronic hepatitis which worsened extremely in 2009. And in 2011 I threw him out into the street. I think I know what fear is. And extreme guilt. And the sense of responsibility.
That we know their peril--and our own--makes it more imperative to confront ourselves--not less so. What would it take, for you to tell your son that you choose to bow out of access to his facebook, etc. That you need that--and is there some other way that the two of you can stay connected--if he chooses that, and you too?
What would you need to know or do--for you to do that for yourself, and for him? Or do you feel that it continues to make sense for each of you, that you have this access?