"CONTROL userpasswords2" will give him the ability to change the "log in" passwords, but I don't think it will fix his problem with the "Content Adviser" issue.
Have him try the instructions at this link first and make sure he is logged in as an "administrator":
If that doesn't get it done, then the instructions below are worth checking as this was the manual method that I've used on other Windows systems, although I haven't used in on Windows XP. Make sure he makes a backup of the registry before using these instructions.:
The following steps will remove any password set in the Internet Explorer Content Advisor and allow you to reset the program to its original state.
1) Click on Start and choose Run.
2) Type in RegEdit and select OK.
3) Now click on the little plus sign to the left of H_KEY_LOCAL_MACHINE.
4) Continue to drill down, always clicking on the plus sign at the left of the named key, through Software, Microsoft, Windows, Current Version and Policies.
5) Now click on the Ratings folder.
6) In the right pane of the RegEdit window, you'll see an icon called Key. RIGHT click on it and choose Delete.
7) Next, choose Registry and then Exit to exit RegEdit. You've just deleted your original Content Advisor password.
Restart the computer and run Internet Explorer again.
9) Click on ?Tools? in the upper left, choose ?Internet Options? (or Options for version 3.x)
10) Click on the Content tab and click on Disable. When asked for a password, don't enter anything; just click on OK. This will disable Content Advisor because there's no longer a password.
Hope this helps.
My father tells me that, most of the time when he opens a new window he gets a dropdown "Content Advisor" that will not let him view the window until he types his password and Enter (or check O.K.) Sometimes it comes up several times while moving thru the window. If he removes his password will he be able to avoid this problem? If so, I understand the procedure is Start>Run>type "CONTOL userpasswords2". Then OK. This way he can uncheck any passwords that he does not want, including the Administrator. I do not have XP, so I am doing long-distance guessing.