Ex oh bipolar/alcoholism

[nonsparkle]

To cut a long story short my ex (dd age 4 dad) has struggled in the past with drinking issues. He hadn't touched anything for a long time until the weekend and when I picked dd up yesterday from him as he was being a complete idiot, he wouldn't open the door to me to get her and when he did he tried giving her to me whilst she was just wearing a nighty. (Bearing in mind I had travelled 90 miles on a train to get her).
In the past he has been diagnosed with bipolar also and I think the drinking is somehow a coping mechanism (neglectful childhood/wrong crowd as a teen and drug abuse til he was mid 20s- he's nearly 40 now). He regularly ends up in hospital with drinking related issues/injuries and the last time was with sepsis in his mouth.

My main issue today is my lo picked up on this behaviour and said that he hurt his gf (they live together and she took care of lo) by pushing her which made her cry. I have no idea what to do. Some are saying don't let her see him etc but I'm struggling. I have no help