This is the best advice anyone could ever give fir the situation at hand,are you ready?
MOVE OUT! Problem solved.
I had a problem with my step prick(he just die in horrible car crash few months ago,KARMA) when i was 15.Moved the fuck out & moved in with my brother for about 1 year.By that time they begging me to come back(i was getting survivors bennifits from my dads death).Turns out they realy counted on my money to help with bills.My folks had a social drinking problem(drank in bars only$$$$$$)so they neede me.The step hated it but had to be nice after that.I LOVE IT WHEN A PLAN COMES TOGETHER!!!
Good Luck,hope you guy's work out something cause all you got sometimes is your family,like it or not.