Wow this is a rough one for you and your child....It is possible that this is a better outcome than doing something horrible on the outside though.
All you can really do is focus on you and your child. Of course you will be honest about where he is when you have to be and that is where a therapist should guide you is on what to disclose and how. The number one focus is you and your sobriety and giving a great life to yourself and your child. I know for me, once I had children I felt that meant the decision was no longer there to use....I simply could not. It isn't the same for everyone but the fact that you are so dedicated is great and a year clean is fabulous. Congrats