Dixied,
I also wanted to add that it is very hard on a child to have a father that is in and out and in and out and in and out of their life due to addiction.
I rode this rollercoaster ride with my exah for a very long time and it hurt my son a great deal. I thought I was doing the right thing by allowing him to have contact with our son during periods when I thought he was 'clean'...only to have him disappear from the picture when he relapsed.
Looking back, I wish I had been tougher. I wish I had limited my exah's contact with our son until he had a long-standing track record of recovery. I wanted so badly to do what was right for everyone but sometimes I just didn't know what the 'right' thing was. I always seemed to err on the side of maintaining contact with my exah but it sounds like your DIL errs on the other side. I honestly can't fault her for it.
As someone who's been in your soon to be ex DIL's shoes, I understand why she is doing what she is doing. With the insurance thing...who knows how long your son will keep this new job? How hard will it be for her to switch insurance coverage only to see your son relapse three months down the road...will the child be left without coverage? So many questions...so many ways to look at the issues...Try to trust that your DIL is doing what she thinks is best.