My roommate believes secret gambling rings placed hidden devices inside the walls of his last apartment to spy on and harass him using sonar, "nano particle dust" and radio waves. I've listened to him calmly on at least a dozen occasions describe the reasons he believes this to be the case. I've tried pointing out that all of this seems very unlikely but needless to say it has produced no lasting positive change that in his thinking that I can observe. Now, about a month and a half since he moved in with me he is starting to believe something similar is happening to him here. I have tried to gently direct his attention to alternate and simpler explanations as to why he might be experiencing some of the things he describes but I feel ill equipped to provide the kind of support and care he seems to need and he seems resistant to considering as a real possibility the idea that this is in his head or at all not real. He initiates all conversations on this topic and mostly now I listen passively because it seems pointless to keep pointing out to him how absurd it all sounds when he clearly cannot discern it. Any advice on how to approach this situation would be greatly appreciated. At the moment its not possible for me to move or for him to leave.