He played Everquest 18 years ago and wants to use that same account? He can't; this is a totally fresh server whose login information is independent of what was actually on Sony. You can make a new account by going here:
https://www.project1999.com/account/?LS
More generally instructions for getting started (there are things like launching the game a certain way, and downloading certain special files) are here:
https://www.project1999.com/forums/s...ead.php?t=2651