I am sorry, I did not read into your question enough.
I think the best thing I can do is give you an example of some of the issues my 8yr old is experiencing due to alcoholism/broken marriage between parents (however I am the primary custodial parent):
Anxiety
Easily upset stomach
Attachment issues
Some problems engaging with others
OCD
Isolation
Trust Issues
Fear
I have divorced my XAH, but he is still involved in their lives. For now he remains sober around them. I doubt that will last long as alcoholism is progressive. That is when the problems will really start, because that is when the fight will start to keep them away from him. I am aware a whole new amount of issues will crop up when and if that happens.
I can say that a child who has been moved away from his father, who now resides with an active alcoholic mother, and is around active alcoholic family, will likely have some great issues. How awfully sad. I am wondering if said child was court ordered to be in counseling or receives any counseling? I know that has been a very real help for my children.
The joys of my children outweigh any negative issues I could be having by a million. However, these are my children, so I realize that is different.
My sister and her husband won custody of her step son away from his toxic, bipolar mother. When he became of age, he moved back to his mother. She was a famous manipulator and guilted him into coming back, made suicide threats, etc. It was horribly sad for my sister and her husband. My sister is not able to have children, so this was her only "son." She does have some issues in dealing with this happening.
I don't know if this will help at all. I think the answers will come with a lot of time and observation on your part.
I wish you the best of luck no matter what future decisions you may make!