Dear James,
I haven't got that kind of problems, but I'll recommend you to ask your parents to buy your brother his own computer. If your parents don't have enought money you can make a timetable. Than you'll know when it's your turn to use computer! And if it won't help, than just try to talk to your brouther! Maybe he will understand you! Try not to make a conflict out of it.
Best wishes,
(тут твое имя)