Mapped connection recovery

We have a user who fried his hard drive a few months back. When he got his new drive, he began asking for IT to tell him what network drives he was mapped to. His ntuser.dat file was lost and not covered by the backup, so there’s no way to find the info that way. Is there some tool or script we can run to search all servers in the network and find which file shares his account is authenticated to connect to?