sorry that this is getting worse for you, since you say that you have already counseled with your pastor, and he understands addiction, if i had to talk to someone about this, maybe i would go back to the pastor and explain the situation to him, about this particular, person, and how his decision to help is putting you and your son in danger. i believe that you said that he was working in the ministry too, right? i agree with dragon.
after this, maybe you and your son, could maybe cut off contact for a while until this whole thing settles, like you said, it your life, no one has the right to dictate what you should or should not do or what is good for you to do. its none of his busness, and if ah wants to include him, then fine, just don't allow them to bring their opinions to you.
sorry but if this mutual friend is relaying all of these messages, maybe you can ask them to hold off for awhile too. what you don't know can't hurt. somethings are good to know but not all things. have you thought about the motive behind what this mutual friend is telling you and why? try to continue with your plans if thats what you choose to do, and if you want, you can change your mind latter. still praying for you.