Oh shit. I think you should find a good anti-virus and fast. He could steal some of your personal data like credit card numbers etc...
I keep trying to, but my portable hard disk became all shortcuts(including my used space, from 100GB became 14GB), but I still can access...
Luckily, i manage to install free trial of Malwarebytes' Anti-Malware, my parents still don't really care about this kind of problem, what they care is my exam because it is coming soon... I need help....
I think my facebook has been hacked too because once my brother saw me post something that i didn't do it.