I don't see how you need to "evict" him, when he's not your tenant. All a lawyer can do is type up a fancy letter saying, essentially, "Get out." You'll still probably need local law enforcement to enforce your "notice to vacate."

You're not just now, after 3 years, finding out that this guy is an obnoxious loser. You've created a dependency by letting him hang around so long. Keep in mind he's using illegal drugs, probably bringing them into your home.

You've kept him there probably because you became lonely living by yourself. Now, with your son there, you have another source of company, so you don't feel such a need for the boyfriend.

It is hard to throw someone into the street. He'ld probably claim you invited him to stay there in exchange for him doing some work for you. Over the course of 3 years, he probably has done a project, or two, around the place.

You can give him a written letter telling him that you withdraw your permission to let him stay and set a deadline for him to leave. He'll just stick around. so you'll need to go to the police station and file a written complaint against the guy. Then, you'll need to call the cops on him to pull him out. A lawyer isn't going to make any of this easier.

It's a tough situation to be in . . . morally. Wait for the Spring, if you like. but you're going to need to do it.