I have seen that many site administrators periodically report the issue of the Profile Synchronization job not updating the details of their users in their SharePoint sites.  In all the cases people have reported that the user details were updated in AD subsequently published in the SSP after profile import.  However these details are not pushed down to the site collection level.

So I am mentioning some points here about this issue:
  1. The profile synchronization jobs responsible for updating these details from SSP to sites only updates details for the active users.
  2. The active users are considered as the users who have carried out any change in the site ever in any form of add, update or delete.
  3. The active users are marked at the database level. In the content database there is a table UserInfo used to store details of all site users.
  4. In this table there is a column named as "tp_IsActive". This column is a type of bit column and will carry the values 0 or 1. the value 1 stands for an active user and 0 for an inactive user.  
Refer to this article: http://msdn.microsoft.com/en-us/library/c6244ace-4199-450d-a215-d37fa591159d(v=PROT.13)#active_user

Now to get this to work following steps can be taken:
  1. Ask the user to carry out any changes in the site collection.
  2. Try resolving his correct name by adding him to any user group.
  3. If the first way is not feasible because of your security policies and second is not working out to you then delete the user from site collection and add him once again.