I think programming his own program monitering program would be a bit advance for where he seems to be at. So here are some other suggestions.
1) First if you are on I think Windows Vista or up you can use the parental controls portion of windows. This is where you can set time limits, what programs can and can't be run.
This would be the best option if you want your brother to still be able to use your laptop sometimes to play his game but not all the time. Just give him a set time during the day where he can use it, or say you got 2 hours to play and go into the parental controls and make it so it blocks the game after 2 hours.
Parental controls are built into Windows Vista and 7 which help parents determine which games their children can play, which programs they can use, and which websites they can visit, and most important of all, when can they use the computer. Parents can restrict computer use to specific times and trust that Windows Vista and 7 will enforce those restrictions, even when they’re away from home. Here are some of the features:
You can control when your kids can use the computer
Web filtering has been improved through Windows Live
You can set limits on games
here is the link to the article I copied some out of. http://www.geckoandfly.com/6813/parental-controls-block-video-games-and-set-time-limits-for-computer-usage-and-access/
If you need help figuring out how to use it google
|how to setup parental controls on vista (or windows 7)|
All windows Vista and up have these features and they are free but you will need admin to use these features. If you don't have admin talk to your dad about setting time limits.
2) If you don't want him to use it anymore just change the password on both accounts and he wont be able to log in. You need admin to do this.