This is exactly what I went through for the past two years.  I tried to help my husband with his drug use but he wanted no help for me.  When I filed for divorce he said that he was going to take the kids and that I would never see them again.  My parents paid for a lawyer but legal aid would do just as well.  I was able to pull police records from when he was arrested during our message as well as incident reports for when he started hitting me.  I presented these things to the judge and the judge still gave us joint custody, but......since all this has happened I have had to file for a restraining order because he broke into my house, stalks me and won’t leave me alone.  Finally, he just stopped coming around.  He said that he could not bear to spend time with the children. (OH the DRAMA!!)  The problem was that his visitation was on Friday and Saturday nights and that was when he wanted to get loaded.  Eventually drugs/alcohol was all that he wanted and my kids have not seen their dad in 6 weeks.  I am going to file for sole custody now and I have documented everything that has happened.  The kids don’t even want to see him.

Good luck and it will work out for the best.