There are also a myriad of software programs (basically legal trojan-horses) that can be installed that hide from the user, and send daily reports back to him.
He's also checking the routers event logs too.
Don't tolerate harassment or intimidation, even though you're a minor. I put up with it, and my life has been worse for it.
If you're up against a wall, do what you need to to have a modicum of privacy. Once you're 18, get the hell out, and never look back. Parents that think they can hold their children under their thumbs because they are "minors" deserve no loyalty...or love!