As I said to Perplexed, he lives halfway across the continent. I do know his name and mailing address, but I talk with him exclusively over IRC. I know some of the therapies and medicines he's taken, but I don't know what he's taking right now.

Part of my reluctance to take matters into my own hands is that I don't know how to reliably tell a qualified psychiatrist or psychologist from a quack. I can look up what Wikipedia says about a specific therapy like ECT, but how do I know whether what it says is accurate enough to trust my friend's life to it? As the status quo seems unlikely to have a catastrophic turn for the worse, I'm reluctant to do anything that would change it without either a strong confidence in its efficacy or at the very least a strong confidence that it will do no harm.