I think he want control over the pc, that he can like close all open apps when the brother is on the comp.
You can install a trojan horse. U just install a server on ur brothers machine. Then u write his ip, into a program you have on ur comp. Then u can see whats he is doin, and you can close apps, and todaly mess with him:)
There are many good trojans out there, but mostly, they are detected by av. So if ur smart, u dissable AV when ur on his computer installing the trojan:)
If u didnt get it, AV is antivirus :)