If this is the forum account they are create with, should be able to see them on the management page:
https://www.project1999.com/account/?LS
The client also keeps record of the last account that was logged in. Look for eqlsPlayerData.ini in the main EQ directory and it'll have something like
[PLAYER]
Username=xxxxxxxx
Password I believe the only way to reset it is through SMS. Should see options for it with the link above