Restore just his account. Restoring from a backup doesn't mean you have to restore everything. Open the .sql file in a text editor, find the user table and his account and run a query to insert the values. All the code you need will be right there with the user table all you need is the following and run it in the sql query window.
Code:
INSERT INTO user VALUES('X', 'X', '', 'X', 'XXXX', 'XXXX', 'XX', ... etc....);