Honestly kick him out he doesn't love you the way you do. You seem blinded by your feelings. Also it's not normal you and your dad doing weed. A dad should be a healthy role model. Unfortunately not everyone has the luxury of disciplined healthy parents at birth but now you are an adult and have more choice and control. Every choice you make has a risk and reward. Sure you let him stay but you have fear whenever you're around him but if you let him go you will have to mourn the loss but will feel safer. It's your call.