I recently did this in the same order and it worked with a CH 3 guy, only he didn't say "don't bother me". Instead i got all the dialogue options to complete the quest, found the target and let him and his daughter go. So...could it be you are talking with the wrong guy? Too many shady characters in this world.
Good point about the VC Medical Investigation because it has such similar requirements, one might wonder if those two quests might step on each other. But the dialogue options are different so it's possible if you got both quests at the same time, you could ask 4 people at each station for the doc, then ask the same 4 people again for the Man's Job, and move on to next station doing both quests concurrently.Regardless, for this reason i completed the Medical quest first, then got the Man's Job and it worked just fine.
(I have spoken to the other 3 people at the station but this makes no difference).Anyone got any ideas?