Not knowing is something that is so hard for me. But no answer is sometimes all the answer you can get. I was raised that you see a problem - you fix a problem. but that isnt how it works in the real world.
You are so right to focus on your daughter - she needs this. I have become determined that my daughter's special times will not be destroyed by someone else's addiction or problems. My AS was tripping on acid at her 10th birthday party last year - I just completely avoided him until it was over - I didnt even acknowledge it or allow my brain to go there - just kept busy and kept that smile on my face until i could go to bed and let it all out.
In the words of Scarlett O'Hara “Fiddle-dee-dee! I won’t worry about that today. I’ll worry about that tomorrow. After all, tomorrow is another day!”