Hi and welcome, Sumsky
BBU and SWOT have given you great advice.
None of this is your fault, but you seem to be left holding the bag on this. You are not overreacting.
I have a 12 year old daughter, as well as older step sons (they are adults, now).
If there was even a hint of any impropriety toward my daughter by anyone, that person would no longer live in my home.
If it were me, the choices would be that step-son leaves immediately, or my kids and I would be getting an apartment tomorrow. Your step-son’s counselor is way off base. I am concerned for the safety of your daughter and any friends she brings to the house. I would be extremely upset if I found that a parent of my daughter’s friend had this situation in the home and my daughter was potentially in danger.
You are the only person in this situation that seems to be on the side of the victims. Everyone else seems to be more concerned about the well-being of the perpetrator. Even if it is true that the young man has learned his lesson, and will never do this again, how can you know this is true? They want you to gamble with your daughter’s life that they are correct? The price is too high.
Trust your instincts.
Apple