How do I support my friend?

My best friend and her boyfriend have been together for 3 months they did previously date at the start of the year but split up after he cheated on her, me and the boyfriend do not get along after he said some pretty harsh things about me during a hard time in which my best friend took his side and kept him around and the hard time didn’t get better until he cheated and was ultimately out of the picture I have no intention of ever having him be apart of my life as much as he’s apart of her life i don’t like the mental distress that the memories of what he said and did to me during this extremely hard time even when he came back he caused me a lot of extreme stress although at the time I had good support in place which helped me deal with it slightly

Last month my best friend opened up to me and said that she wanted to end the relationship and that he wasn’t making her happy etc that he was extremely controlling and that she didn’t like how that made her feel she expressed to me that she felt in the future she could see him becoming abusive given some of his previous outrages and actions in which she decided that she should end the relationship

I’m currently pregnant and have been suffering from hyperemesis so have been extremely sick and in and out of hospital I had been feeling better the last few days and my friend and I finally got a proper catch up on everything and the last we’d properly talked about it she was keeping her distance from him and slowly removing him from her life, so we caught up today and I found out that he’s been pretty much living with her he keeps things there he gives money for food electric, gas etc, staying at her house even when she’s at work (something she was extremely against around a month ago) and he even met her family which she didn’t want to do the last time we properly talked we have talked while I was sick but it was more of a how are you how’s things (although she’d never mentioned she’d seen him or even any of these things)

I just don’t know how to support her with this because I’m obviously never going to want to have him in my life at events like weddings or anything related to my baby and we’ve talked about her babysitting my baby and stuff and it’s going to be hard for me to trust that he’s not going to be there when she didn’t tell me that he was living there to begin with I want to support her with everything she does but it’s extremely hard for me to support him when I know how shitty of a person he is and her previous concerns that I don’t see how they could have vanished so suddenly