There isn't exactly a whole lot we can do here. As far as we know none of them are here and chances of him remembering any idea that does form isn't one he'll remember back home. However, there's nothing stopping us from investigating should they show up. [Conan is keeping up the appearance of a seven year old and Shinichi is still technically only seventeen - still a teenager and probably not likely to get many adults to let him investigate something so dangerous.]

We're the only ones here who can help him. Back home he has a handful of individuals who know the truth, who can help him out and I've no doubt that he needs it from time-to-time. He just... doesn't trust us enough yet. Given time it's likely he will. After all, we didn't only go to his world just because I was his doctor.