Since I deal with a lot of the educational software I might be able to help, but "medical simulator" is rather vague. Can your client provide a bit more info on what he is trying to simulate? The list of what medical "things" that could be simulated on computer software is endless!
I'm putting a system together for somebody in medical school and he mentioned needing medical diagnostic simulator software. He said that he had this once before quite a while ago on a floppy disk for an older computer he had, but he's not sure if there's anything available out there now on cd.
Does anybody have any ideas? I've looked a little through google, but it appears that most of what comes up for me is actual simulator equipment and not software for the pc.