I've been following your story and I always admire how you rally even after an emotionally abusive episode by him.
In my professional experience with mom's seeking custody (not as an attorney but as a mental health person for the child), no judge in their right mind would give much custodial weight to a man with a history of violence or substance abuse even if he is not currently drinking. If they did they would make him submit to psych testing etc (again this is in my experience only).
Your experience mirrors one I was helping a mom out with. He was very abusive, had expensive attorney but the court maintained her custody rights because they could see right through him. This is a mom with health issues, no job, she was sometimes even homeless but the judge still made her custodial parent.
That should reassure you I hope. Any man with a history of substance use and abuse has an uphill battle no matter how rich and powerful he is. Kids safety is paramount.