What problems is he having?
Remember, new accounts must be created here (send him to
http://www.thebritishsteeliessociety.co.uk/ucp.php?mode=register), login details from the old site will not work.
He should also use a valid email address to register as an activation link will be sent which must be clicked. If it seems this doesn't arrive, tell him to check any spam folder(s) or filter(s).