My son 17 has been smoking weed and it has started to affect his day to day life, he has lost all motivation for college and turning up late to college, not handing work in and not interested in anything he does anymore. it has affected his mental health, our relationship is at an all time low he shouts and swears and gets very angry. He treats the house like a hotel and thinks he can come and go as he pleases. He tells so many lies and i just don't believe a word he says anymore. There is so much disrespect. I am at my wits end and just don't know what to do anymore. How can i help him?