I really don't know the answer to this but I'll throw it out there anyway. Could he be suffering from PTSD from the horrible experience he had with the Strattera? I mean he was living in sheer terror for how many days? I can't imagine that he doesn't have some lasting effects from the terrifying hallucinations alone. And to be only 5 years old when it happened. I can't imagine how that would feel as an adult, let alone such a small child. I really hope you're able to find someone to help him.
If he's not hallucinating and acutally seeing bugs, here's an idea that I wonder if it would help. Have you seen "Monster Spray" for kids who are afraid of monsters? It is actually an aromatherapy spray that kids think is a monster repellant. They spray it to keep the monsters away and the aromatherapy is supposed to help them relax. Maybe you could come up with a recipe for "Bug Spray" that he could help you make and he could have it in his room to spray anytime he thought there was a bug. I'm sure you could do an internet search and find something. I would go so far as to type up a colorful recipe for it with a claim that it guarantees no bugs will come near and tell him you found it on the internet. Just hope that no bugs really do show up! Just a thought. It's worth a try.
