BD in a emotional relationship

My bd is in emotional abusive relationship. I know this sounds crazy, but my daughters dad and I are best friends. No we are not together we broke up 5 years ago but became so close these past 2 years . He opened up to me about his other child’s mother who he is with rn and how he tried to leave but she says she is going to take the kid away from him and put him on child support . At first I thought he was just making that an excuse to not leave but I talked to his parents and they even over heard a conversation where she did say that. He is absolutely terrified to loose his daughter but he is so unhappy with her . I try to tell him he has a better chance having at least more custody or at least 50/50 bc he lives with the baby + buys everything for her and more I even pay for some of the babies necessities I, myself got her clothes and shoes and food that she needed his gf also does drugs and he does not bc he is in the military and can’t do I feel like it won’t be to hard to fight in court but he is also a black male and she is white female so that makes a slight difference as well . I feel bad for him bc he is not a bad person and not a bad father but he wants to leave a relationship and I know he feels guilty for wanting to leave . I also dont want our daughter together being around toxic behavior . And before you guys start saying “he is just saying this stuff to make you feel bad for him” . It’s not that at all I had to literally drag it out of him bc I knew something is wrong . I don’t know what to do he seems so depressed when we talk on the phone and are not with each other. But when he comes to visit he is so happy and himself.He calls me at least once a week crying that he wants to come back home and it breaks my heart bc I Truly want him to be happy and healthy for our daughters sake . I’m going to start getting his old room together and hopefully that pushes him to leave.