One other thing, you say it is your parents who want to use the internet, and it is your brother who wont switch on his PC.
Can they not exercise some parental control and say that unless he allows them to use the interent they will stop him using it, or stop paying for it.
After all, they are the parents, he is the son (not sure how old his but he is still their son).
If he still wont play ball they can suggest he moves out (if he is old enough).
Sorry to be so harsh but he seems to be exercising a lot of power here.