You need to tell your son that no one is allowed at your door after such and such a time at night, or before a certain time during the day. If you truly think he's dealing from your home, you may want to call the police, or you can drug test him and if he's using, tell he to get out. You should never have to live in fear in your own home. I threw mine out for using, so I certainly wouldn't have put up with him dealing from my home.
sounds like you need to get a plan in place to protect yourself. If people are coming into your home buying drugs, then I'm sure things will start missing soon.
I'm sure others will be along shortly to give you some more advice and support.
