Usually the PMs get sent to your e-mail. I don't know if the ID shows up though. If he knows an approximate date of when the PM was sent, and maybe even the recipient's name that should be ok though. Just tell him to add as much information as he possibly can.
He should also take some time to carefully think of all the information he could possibly provide, because the admins seem to get flooded with requests, so he will want to make sure that his one shot counts. Don't send a ton of PMs, it will probably work against him.