My gut response to this is to tell you to openly share in a meeting what's going on.
Your own recovery is obviously suffering because of it.
You are not responsible for this man and you have no business trying to protect him or his pigeons when you are in so much pain.
On the other hand you could continue to remain mute and allow the spiritual principles of acceptance and courage to work in your life.The truth will ultimately be revealed.
You have to choose.Your indecisiveness is only going to make things worse.
What is more important to you? Your recovery ,or your fear of him?
You might actually be doing him and your group a favour if you share about it.