This is a very tough issue. When you throw alcoholism/addiction into the mix, it complicates it even further. I think that awareness is important. I have no doubt that had I been aware of the issue of parental alienation and the effects on my son, I would have done some things differently.
I admire my son's XGF because she seems to have found a way to manage her relationship with me (the grandmother/mother of her ex), her sweet son, and her XABF (my son). She gets together with my son with their son and have family time. They go to the zoo or to a little festival or just walk in the park together. She allows my sweet grandson to spend 2 - 4 Saturdays a month with me and encourages my son to spend time with him here. They all came over to our house for the last two Saturdays and swam in our pool and played as a family unit.
She is very clear about her boundaries. If my son relapses and gets weird, she will only allow supervised visits or no contact at all. I support her in these decisions. As a result of her very healthy perspective, my son is directly responsible for the amount of interaction he gets with his son. When my son relapsed a couple of months ago, he got very weird.....he was unstable. She and I discussed it and both agreed that it was not healthy for the little guy to spend time with his father when he was unstable. Shortly after that my son put himself back into intensive outpatient treatment.
Things have been going extremely well since then and he is finding that he can spend lots of time with his little boy. It just makes sense.
All of this would have been very difficult for me when my son was little. I could barely stand to be in the same vicinity of my XAH. But that was MY problem that I needed to deal with for the sake of my son......I just wasn't aware of how subtle (and not so subtle) actions on my part were harmful.
It's all about self awareness........and I'm getting better at it. Better late than never.