Forget about him or give it a try?

I would say to wait it out. Just because he initially liked your friend doesn't mean that he doesn't like you. Just be his friend for now and see where it goes. You never know, he could turn out to be a great guy. But if you have a problem with the fact that he gets stoned and smokes then you may need to try to remain his friend. I knwo you are trying to get into a relationship right now but you have to breath and take your time and realize that your perfect guy is worth the wait. And it's ok to make mistakes: maybe he's the guy to show you how horrible a guy can be so that you would appreciate a great guy. Live life.