Then he would be adjusted for games and everything on the rest of his PC would be too dark or contrasted.
It could be that his standard gamma settings are off enough that they are affecting everything. Unlikely but worth a shot.
It is more likely that the slider is based around a lesser contrast range. If his contrast range were worse, the low blacks would disappear faster, not quicker. That is what you see in old school games that were made for CRTs, so you never get things very vibrant (only hitting median between too dark or washed out, and always a bit bland) unless they provide all options like Killing Floor does. The only time it would go quicker is if the software were compressing the contrast like the full/limited mentioned earlier. I don't think that is the case here, though. What happens here is the opposite of the old school games, so that a low black hitting there visually on most TVs is going to make a lot of things that are more high-point on TVs mid-point to his monitor, so they come out displaying brightly, yet in truth there isn't as much contrast, so there is less subtlety in the tones on the TV as possible on the computer and it's overall dim on PC.
