I'll point out that this sounds very much like Matt suffers from schizophrenia. I know this illness well as someone very close to me suffers from it, and when unmedicated behaves pretty much exactly like that. That's not to say the situation is any less dangerous, but probably not because someone is going to kill Matt--more likely because he'll get himself into dangerous situations because of his dramatic misinterpretation of events. Schizophrenics without friends and family to help keep them out of trouble, and medicated as necessary, often wind up in prison.
If my from afar diagnosis has any basis in reality (which it very well may not--I'm not a psychiatrist, and I only know what the website told me), the fact that Zed posted all of this information will very likely be taken as a sign that Zed, formerly a "friend" worthy of trust in a dangerous situation, is now Matt's enemy. Family and lifelong friends are not immune to this effect, so I'm certain a random stranger who wrote some nifty software won't be. Anything said or done that doesn't match precisely the worldview of a schizophrenic is viewed with suspicion, and very often the worldview changes from minute to minute as the mind flits from one misinterpretation to the next. This may explain why Zed can't get in touch with him: Zed is obviously part of the conspiracy, and his trying to call him frequently merely confirms it (there is no "right" action here; Zed certainly hasn't done anything wrong, it's just the way things go in the mind of a schizophrenic).