A mod isn't necessary; you can change the con colors in your options.
Just go to
Options > User Interface > Game Colors and scroll down to find "
Con Too Easy," "
Con Easy," "
Con Mild Challenge," "
Con Even," "
Con Tough," "
Con Very Tough," and "
Con Extremely Tough." Your friend can change these to whatever colors he likes.
Also, in
Options > User Interface > Name and Chat Bubble > NPC Evaluation, if you choose "
Simple (Frames)," you'll see the mob's actual level in a circle to the left of its name over its head when you target it. You can still see how many arrows it has and whether or not it's heroic in the target window.
As far as changing the "aggressive" outline around a mob's name, I haven't found anything in the options that will allow you to do this. When you mouseover the target window, though, you'll see a tooltip that tells you whether or not a mob will attack you when you are in its aggro range. Any mobs that say or "
This creature scowls at you, ready to attack!" will attack; any other messages (threatening [an aggressive mob that's greyed out?], indifferent, ally) will not.
To break down the tooltip, you'll see the info in this order:
Mob Name (mob level)
Health: percent%
Whether this mob is soloable or heroic
How difficult this mob will be for you to defeat
How this mob regards you (scowls, threatening, indifferent, ally)
A textual estimate of how defeating this mob will benefit you
Have you considered asking him to let
you select and pull the mobs the two of you will be fighting together?
